JPH11177897A - Satellite receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a highly accurate and quick AFC operation and to provide a second local oscillation signal of an indoor tuner with reduced noises. SOLUTION: A first local oscillation signal 12 is frequency-divided with a frequency division ratio N in a 1/N frequency divider 109 and outputted from an outdoor converter 102 along with a first IF signal group. In the indoor tuner 103, a 1/N frequency-divided first local oscillation signal 115 is taken out by a band-pass filter 120, a difference with a signal from a crystal oscillator 123 is taken by a mixer 121 and the frequency is multiplied by N at a PLL constituted of a phase comparator 124 and the 1/N frequency divider 127, etc. Then, mixing with a VCO output signal 33 is performed in the mixer 135 and only difference components are defined as a second local oscillation signal 147. When the frequency of the first local oscillation signal 12 fluctuates, the second local oscillation signal 147 inversely changes and the frequency of a second IF signal 40 is fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a parabolic antenna, an outdoor converter, and an indoor tuner, and receives and demodulates radio waves such as satellite broadcasts and satellite communications transmitted from artificial satellites (hereinafter abbreviated as satellites). In particular, the present invention relates to an AFC (Automatic Frequency Control) operation system.

[0002]

2. Description of the Related Art In the use of satellites in the field of broadcasting and communication, frequencies in the GHz band have been conventionally used. As a typical example, radio waves in the vicinity of the 6 GHz band or in the vicinity of the 14 GHz band are used as uplink lines to the satellite. The signal is transmitted to the satellite, and the radio wave is transmitted to the vicinity of 5 GHz band or 12 G
It is converted to radio waves in the vicinity of the Hz band and used as a downlink. A satellite receiver is used to receive and demodulate this downlink radio wave.

A general satellite receiver includes a parabolic antenna that captures radio waves from a satellite and converts the signal into a signal, and a first IF signal group of about 1 GHz band for drawing a signal from the parabolic antenna indoors by a coaxial cable. It comprises an outdoor converter for conversion and an indoor tuner for selecting and demodulating only a signal of a desired channel from the first IF signal group. In recent years, research on practical use of digital multi-channel broadcasting, data broadcasting, digital satellite communication, etc. has been actively conducted, but in both broadcasting and communication,
The same applies regardless of whether the modulation method of the satellite radio wave is digital or analog, and whether the transmitted signal content is a video signal, an audio signal, or other data. However, in the case of a digital satellite receiver that receives a digitally modulated wave, a higher A because the synchronization pull-in range of the demodulation circuit is narrower than that of an analog satellite receiver.
FC accuracy is required.

Here, the necessity of the AFC function of the satellite receiver will be described. For example, IEICE Technical Report V
ol. 87, no. 285p. 13-17 (SAT87
According to "-45), 1987," Development of repeater for broadcasting satellite No. 3 (BS-3) "
+1.2 parts per million and -2.3 in the temperature range of degrees
The frequency fluctuation is within the range, and the frequency stability is very high. Therefore, the frequency control circuit of the local oscillation signal of the satellite receiver uses a PLL (frequency phase locked loop).
In this case, the frequency of the local oscillation signal is controlled with a high precision of about one millionth to several tens of hundredths, which is equivalent to that of a crystal oscillator. do not need.

However, in the satellite receiver, the first local oscillation signal frequency fluctuates with respect to time and temperature due to poor environmental conditions that the outdoor converter is installed outdoors. For this reason, for example, the Radio Technology Association of Japan
As described in the Satellite Broadcasting Reception Technology Investigation Committee Report, Part 2, Satellite Broadcasting Receivers (No. 2 Desirable Performance) issued in September 2008, an outdoor converter (BS in this reference)
It is described as a converter. The first local oscillation signal frequency of the first local oscillator in (1) is 10.678000 GHz including error and drift in consideration of the easiness of manufacturing the receiver and the poor environmental conditions of being installed outdoors.
The allowable regulation values are defined for the fluctuations up to +1.5 MHz and -1.5 MHz with respect to.

For this reason, an indoor tuner of a satellite receiver needs an AFC function for correcting these errors and drift and keeping the reception frequency within a regulation value. Although the above description has been made with respect to satellite broadcasting as an example, this is not limited to satellite broadcasting, and outdoor converters used for other satellite communications have the same performance, and it is fundamental that an indoor tuner needs an AFC function. Is the same as

As the AFC method of this satellite receiver, mean value AFC, keyed AFC, and the like have been put into practical use, but all of them mainly use an indoor tuner to estimate and compensate for an error. There is no AFC system that actively corrects the local oscillation signal frequency error or drift.

In the frequency synthesizer receiver described in Japanese Patent Application Laid-Open No. 1-164130, a tuner unit and an IF / PLL unit 1 are superimposed by superposing a plurality of signals.
The front end described in Japanese Patent Application Laid-Open No. 63-040421 outputs a local oscillation signal after frequency division in a front end housing.

[0009] Further, the AV equipment with a built-in satellite broadcast receiving unit described in JP-A-07-079430 detects a keyed AFC signal and controls the equipment.
No. 37629 describes a satellite broadcast receiving apparatus which is a digital A
Invention sharing crystal oscillator required for FC,
The AFC adjusting device described in JP-B-135622 is an invention for realizing an AFC device that is easy to adjust.

However, the above-mentioned conventional invention does not improve the accuracy of the AFC function of correcting an error or drift of the first local oscillation signal frequency.

Next, the operation of the conventional satellite receiver and its AFC method will be described with reference to the drawings. The following description is
Although the case of satellite broadcasting in Japan is taken as an example, the present invention can be used not only for satellite broadcasting but also for satellite communication and other fields as long as the frequency relationship is known in advance.

FIG. 17 is a block diagram showing the configuration of a conventional satellite receiver, and FIG. 18 is a block diagram showing a received signal group 11 from a satellite and a first signal.
FIG. 19 is a signal frequency array diagram for explaining the relationship with the local oscillation signal 12, and FIG. 19 is a signal frequency array diagram of the first IF signal group 13.

This conventional satellite receiver comprises a parabolic antenna 1, an outdoor converter 53, and an indoor tuner 54.

The parabolic antenna 1 receives a radio wave from a satellite and outputs it to the outdoor converter 53 as a reception signal group 11.

The received signal group 11 has a center frequency of 11.72748 GHz to 11.9966 as shown in FIG.
The signal is an eight-wave signal having a channel interval of 38 GHz and a channel interval of 38 GHz, and odd-numbered channel numbers BS-1 to BS-15 are assigned.

The outdoor converter 53 includes an amplifier 4, a mixer 5, a first local oscillator 6, and a band-pass filter 58.
It is composed of

The amplifier 4 amplifies and outputs the received signal group 11.

When receiving a 12 GHz band satellite wave, the first local oscillator 6 normally outputs a frequency signal in the vicinity of 10 to 11 GHz as the first local oscillation signal 12, and the frequency is determined by the satellite system. For example, in the case of satellite broadcasting, the frequency is 10.678 GHz.

The mixer 5 mixes the signal output from the amplifier 4 and the first local oscillation signal 12 and outputs the mixed signal.

The band-pass filter 58 has a center frequency of 1049.48 MHz which is a difference between the received signal group 11 and the first local oscillation signal 12 among the signals output from the mixer 5.
, And passes only eight signals in the 1GHz band of 1318.00 MHz to output as the first IF signal group 13.

The indoor tuner 54 includes a tuning amplifier 16 and
Mixer 17, IF circuit 18, demodulation circuit 19, pre-frequency divider 56, programmable frequency divider 24, reference signal oscillator 25, phase comparator 26, low-pass filter 2
7, VCO (voltage controlled oscillator) 28, control CPU 5
5 and a channel selection instruction section 32.

The tuning amplifier 16 selects, amplifies, and outputs the first IF signal group 13.

The mixer 17 mixes the output signal from the tuning amplifier 16 and the VCO output signal 33 from the VCO 28 and outputs the resulting signal.

The IF circuit 18 includes a band-pass filter, an amplifier, and the like, and outputs a signal having a certain frequency among the output signals from the mixer 17 as a second IF signal 40.

The center frequency of the second IF signal 40 is usually 134.26 MHz, 402.78 MHz, 479.
5 MHz or the like is used, but here, 479.5
The case where MHz is used will be described.

The demodulation circuit 19 demodulates the second IF signal 40, outputs a demodulated output 36, and inputs the input second I signal.
Information as to whether the center frequency of the F signal 40 is higher or lower than 479.5 MHz is output as the AFC signal 46.

The AFC signal 46 is a signal representing information indicating whether the center frequency of the second IF signal 40 is higher or lower than 479.5 MHz in terms of the voltage level, or a signal converted into a serial or parallel digital signal sequence. . When the voltage is expressed by the level of the voltage, the center frequency of the second IF signal 40 becomes 4
It becomes a certain reference voltage at 79.5 MHz.

The demodulation performed by the demodulation circuit 19 is generally FM demodulation in the case of analog transmission, and demodulation such as QPSK or 8-phase PSK in the case of digital transmission. And
The demodulated output 36 is video information, audio information, and other data, and each signal processing is performed by a circuit at the next stage of the indoor tuner 54 (not shown).

In the indoor tuner 54, the pre-frequency divider 56, the programmable frequency divider 24, the phase comparator 26,
The low-pass filter 27, the VCO 28, and the reference oscillator 25 constitute a so-called PLL (frequency phase locked loop).

The pre-divider 56 divides the frequency of the VCO output signal 33 by a fixed dividing ratio and outputs the result. The programmable frequency divider 24 further divides the frequency of the VCO output signal 33 divided by the pre-frequency divider 56 at the frequency division ratio set by the programmable frequency divider setting signal 23 and outputs the resultant signal.

The reference oscillator 25 outputs a signal having a frequency of 10 kHz as a reference for the PLL control as a frequency reference signal. Here, the frequency of the frequency reference signal is 10 kHz.
However, the present invention is not limited to this frequency and other frequencies, for example, 20 kHz, 12.5 kHz,
In some cases, 25 kHz or the like is used.

The phase comparator 26 compares the phase of the frequency reference signal output from the reference oscillator 25 with the phase of the signal output from the programmable frequency divider 24, and outputs the phase difference as a phase error signal.

The low-pass filter 27 includes a phase comparator 26
Converts the phase error signal output from the
It is output as the O control signal 30.

The VCO 28 generates a signal having a frequency determined by the voltage of the VCO control signal 30 and outputs the signal as a VCO output signal 33.

In the case of the upper local oscillation system, the control CPU 55 sets the frequency division ratio of the programmable frequency divider 24 with the programmable frequency divider setting signal 23 to thereby output the VCO output signal 33 output from the VCO 28.
Is changed to the frequency in the first IF signal group 13 of the channel designated by the tuning instruction unit 32.
Control is performed so that a frequency obtained by adding the center frequency 479.5 MHz of 0 is added. For example, 1318.0 of BS-15
When selecting 0 MHz, the frequency of the VCO output signal 33 is 1797.5 MHz obtained by adding 479.5 MHz.

The channel selection instructing section 32 is for selecting a broadcast station to be received and instructing the control CPU 55. Specifically, the channel selection instructing section 32 is provided on the front surface of the housing of the indoor tuner 54 and the like. It is composed of an up / down button for a station, numeric key buttons, a remote control light receiving section for receiving a signal from a remote control unit or the like.

Next, the operation of the conventional satellite receiver will be described.

The incoming radio wave from the satellite is transmitted to the parabolic antenna 1
As shown in FIG. 18, the received signal group 11 captured at the center has a center frequency of 11.72748 GHz to 11.99600.
These are eight-wave signals of GHz, and are assigned channel numbers from BS-1 to BS-15 as shown in parentheses in FIG. In the case of satellite broadcasting, since the frequency of the first local oscillation signal 12 is determined to be 10.678000 GHz, the first local oscillation signal 12 is located below the reception signal group 11 as shown in FIG. ing. And
The received signal group 11 is amplified by the amplifier 4, mixed with the first local oscillation signal 12 which is the output signal of the first local oscillator 6 by the mixer 5, and is received by the band-pass filter 58. Only the difference between the signals 12 is selected and output as the first IF signal group 13.

As shown in FIG. 19, the first IF signal group 13 includes a reception signal group 11 from a satellite and a first local oscillation signal 1
A group of eight signals in the 1 GHz band having a center frequency of 1049.48 MHz to 1318.00 MHz, which is the difference between the two, is transmitted by a coaxial cable and input to the indoor tuner 54 in FIG.

In the indoor tuner 54, the first IF signal group 1
3 is output after being selected and amplified by the tuning amplifier 16.

Here, when a channel selection operation of selecting a signal from eight signals of the first IF signal group 13 is performed on the channel selection instructing unit 32, the channel selection instructing unit 3
2 instructs the frequency to the control CPU 55. And
In the control CPU 55, the frequency of the VCO output signal 33 is
The PLL is controlled by setting the frequency division ratio of the programmable frequency divider 24 by the programmable frequency divider setting signal 23 so as to be a frequency obtained by adding 479.5 MHz to the designated frequency.

For example, when the tuning instruction of the BS-15 is issued from the tuning instruction section 32, the frequency of the reference oscillator 25 input to the phase comparator 26 is 10 KHz.
The total frequency division ratio of the pre-frequency divider 56 and the programmable frequency divider 24 is 179750 since it is a value obtained by dividing 1797.5 MHz by 10 KHz, and the control CPU 55 outputs the programmable frequency divider setting signal 23 to output the programmable frequency divider 2.
4 is controlled so that the total frequency division ratio becomes 179750.

Then, the signal output from the tuning amplifier 16 is mixed with the VCO output signal 33 in the mixer 17, and only the signal of 479.5 MHz is selected by the IF circuit 18 and output as the second IF signal 40. The second IF signal 40 is demodulated by the demodulation circuit 19 to obtain a demodulated output 36.

In this conventional satellite receiver, the pre-divider 5
The frequency of the VCO output signal 33 is 10 kHz when the total frequency division ratio of the VCO 6 and the programmable frequency divider 24 changes by 1.
Only change. Therefore, the control CPU 55 can control the frequency of the VCO output signal 33 in units of 10 kHz by changing the programmable frequency divider setting signal 23.

Here, since the AFC signal 46 is inputted from the demodulation circuit 19 to the control CPU 55, the control CPU 5
5 is to monitor the AFC signal 46 at all times,
It is possible to know how much the center frequency of the IF signal 40 deviates from 479.5 MHz. And control C
The PU 55 performs control so that the center frequency of the second IF signal 40 is always 479.5 MHz by appropriately correcting the deviation in units of 10 KHz which is the minimum step frequency of the PLL.

However, in this conventional satellite receiver, since the error in the center frequency of the second IF signal 40 is estimated based on the demodulation result of the demodulation circuit 19, the demodulation circuit 19 causes the demodulation circuit 19 to change its environment due to temperature change or the like. In the case where the center frequency reference value drifts, the control CPU 55 mistakenly recognizes this movement as an error of the center frequency, and the AFC operation is performed in a direction to increase the frequency error. There is a possibility of causing malfunction.

If the drift of the center frequency reference value is to be minimized in preparation for an environmental change due to a temperature change or the like in order to improve such a problem, a very expensive precision component is required in the demodulation circuit 19. , The reference value must be adjusted with very precise fine adjustment, and sufficient manufacturing control must be performed even with respect to temperature and environmental changes, resulting in an increase in cost.

Further, since the second IF signal 40 is subjected to some kind of modulation regardless of whether it is digital transmission or analog transmission, an accurate center frequency cannot be estimated from the second IF signal 40 and an error is included. There is. Therefore, an accurate AFC operation cannot be performed.

Further, although the original purpose of the AFC operation is to correct the error of the first local oscillation signal frequency and the drift and keep the reception frequency constant, the error of the first local oscillation signal frequency is maintained. And the drift is replaced with another signal such as the second IF signal 40, the AFC operation cannot be accurately performed in a short time in conjunction with the error of the first local oscillation signal frequency and the drift, and the drift changes. The AFC operation cannot be performed accurately and quickly immediately after the power supply of the outdoor converter power supply which occurs in a relatively short time.

Further, especially in the case of digital transmission, etc.,
QPSK or 8-phase PSK that carries information in the phase direction of the signal wave
In this case, the demodulation circuit 19 uses an error estimation range of several tens KHz to several ones in order to estimate the center frequency error from the phase error.
When the frequency is as narrow as 00 KHz and the frequency error and the drift amount of the first local oscillation signal 12 are large, the error cannot be estimated, so that the correction by the AFC operation is impossible.

In this conventional satellite reception, the control CP
U55 controls the frequency of the VCO output signal 33 by setting the frequency division ratio of the programmable frequency divider 24. However, since the frequency of the VCO output signal 33 can be controlled only in units of the reference frequency of the reference oscillator 25 at the minimum. 2nd IF
An error occurs in the frequency of the signal 40, and a complete AFC
No action can be taken. Even if the reference frequency is lowered, this error cannot be made zero. When performing digital transmission, it is necessary to reduce the phase noise of the local oscillator on the receiver side because information is also modulated in the phase direction.
As a method of reducing the phase noise, the reference frequency of the reference oscillator 54 is increased from several hundred Hz to several MHz to increase the PL.
A general method is to increase the loop gain of L.
However, in order to reduce the error in the AFC operation, the reference frequency of the reference oscillator 25 must be reduced as described above, which is incompatible with increasing the loop gain of the PLL.

Next, a conventional digital satellite receiver and its A
The operation of the FC system will be described with reference to the drawings. However, the present invention can be used not only in satellite broadcasting but also in satellite communication and other fields as long as the frequency relationship is known in advance.

FIG. 20 is a block diagram showing the configuration of a conventional digital satellite receiver, FIG. 21 is a detailed block diagram of a quadrature demodulation circuit 218 in FIG. 20, and FIG. 22 is a detailed block diagram of a demodulation circuit 219 in FIG. It is. The same numbers as those in FIG. 17 indicate the same components.

This conventional digital satellite receiver comprises a parabolic antenna 1, an outdoor converter 53, and an indoor tuner 245.

The indoor tuner 245 includes a tuning amplifier 215
, A mixer 216, an IF circuit 217, a quadrature demodulation circuit 218, a demodulation circuit 219, a signal processing circuit 220,
Control CPU 47 and PLL frequency synthesizer 222
, A control CPU 223, and a channel selection instruction unit 32.

The tuning amplifier 215 is connected to the first IF signal group 13
Is roughly selected, amplified and output.

The mixer 216 receives the output signal from the tuning amplifier 215 and the PL signal from the PLL frequency synthesizer 222.
The L frequency synthesizer output signal is mixed and output.

The IF circuit 217 is composed of a band-pass filter, an amplifier and the like, and outputs a signal of a certain frequency of the output signal from the mixer 216 to the second IF signal 227.
Output as The frequency of the signal output from the PLL frequency synthesizer 222 is equal to the frequency of the signal output from the PLL frequency synthesizer 222 and the first IF signal group 1
3 is the second IF
The center frequency of the signal 227 is set.

The control CPU 223, which has received a tuning instruction from the tuning instruction section 32, executes the PLL frequency synthesizer 222.
By controlling the PLL frequency synthesizer 222 such that the output frequency of the second IF signal 227 is such that the difference frequency of the desired channel frequency in the first IF signal group 13 becomes the center frequency of the second IF signal 227. Is performed.

The center frequency of the second IF signal 227 is usually 134.26 MHz, 402.78 MHz, 47
For example, 9.5 MHz is used.

The quadrature demodulation circuit 218 outputs the second IF signal 227
Are subjected to A / D conversion after quadrature demodulation, and IQ data 228 as two series of digital data on a complex plane is output.

As shown in FIG. 21, the orthogonal demodulation circuit 218 includes a multiplier 238, a multiplier 239, and an A / D converter 24.
0, an A / D converter 241, a 90-degree phase shifter 242, and a fixed oscillator 254. The quadrature demodulation circuit 218 performs quadrature demodulation by injecting and multiplying signals having different phases by 90 degrees from the 90-degree phase shifter 242 into the multipliers 238 and 239, and performing A / D conversion by the A / D converters 240 and 241. After performing the D conversion, the IQ data 228 is output.

As shown in FIG. 21, IQ data 228 is 2
The series is represented by one arrow in FIG. 20 for simplicity. Also, the IQ data 228 at this point is simply the second IF signal 227 as digital data on a complex plane, and is not a completely demodulated signal yet.

In the demodulation circuit 219, the IQ data 2
After digitally calculating 28 and correcting the phase error and the frequency error, it outputs as correct IQ demodulated data 229.
The IQ demodulated data 229 is also a two-series signal.
0 is represented by a single arrow for simplicity.

The demodulation circuit 219, as shown in FIG.
The phase and frequency are corrected by the complex multiplier 248,
The high-frequency component is removed by the roll-off filter 249, and output as correct IQ demodulated data 229. here,
The IQ demodulated data 229 is also input to the phase frequency detector 252, and the phase frequency detector 252 extracts and outputs a phase frequency error component. The digital loop filter 251 controls the NCO 50 (numerically controlled oscillator) by integrating the phase frequency error component output by the output phase frequency detector 252 with the frequency set by the frequency setting signal 231 as the center frequency. And output a control signal for the same. The NCO 50 is controlled by a control signal generated by the digital loop filter 251 and outputs a Sin / Cos signal 53 for controlling the complex multiplier 48. Then, a phase-frequency correction loop is formed such that the error between the phase and the frequency is minimized by controlling the complex multiplier 248 by the Sin / Cos signal 253.

The signal processing circuit 220 outputs the IQ demodulated data 2
After performing signal processing such as error correction processing, extraction of frame synchronization indicating a temporal break of data, and deinterleaving processing of rearranging data in a predetermined order, the processing is not shown in FIG. Predetermined processing is performed by a video, audio, or data processing circuit at the next stage.

The signal processing circuit 220 outputs a synchronization determination signal 232 to the control CPU 247. This synchronization determination signal 232 has many errors in the IQ demodulated data 229 and the signal processing circuit 220 cannot synchronize. The alarm signal is output to the

The control CPU 247 outputs the synchronization determination signal 23
When 2 is output, the frequency setting signal 231 is changed, and the center frequency at which the demodulation circuit 219 performs demodulation is changed. In this conventional digital satellite receiver, when the frequency of the first local oscillation signal changes and the signal processing circuit 220 loses synchronization, a synchronization determination signal 232 is output and the demodulation frequency of the demodulation circuit 235 changes. Performs frequency control (AFC).

As described above, this conventional digital satellite receiver forms a phase-frequency correction loop that minimizes the phase-frequency error by performing arithmetic processing on the digitized IQ data 228. However, this method has the following problems.

In the correction loop of the demodulation circuit 219 shown in FIG. 21, the pull-in time until the phase frequency error is minimized, the holding strength of the correction loop when C / N (signal-to-noise power ratio) deteriorates, and the like. There is a conflicting relationship with the other performances, and the problem is that the frequency pull-in range of the correction loop cannot be increased.

That is, as described above, the frequency of the first local oscillation signal 12 of the first local oscillator 6 in the outdoor converter is +2 MHz in consideration of the fact that fluctuations up to about +1.5 MHz and -1.5 MHz are allowed. It is desired to pull in the frequency range up to about -2 MHz, but for the reasons described above, actually several hundred KH
Only a pull-in range of about z can be obtained.

For this reason, the control CPU 247 constantly monitors the synchronization determination signal 232, and when the synchronization is lost, the frequency pull-in range is narrow as described above. Each time
The program is set so as to perform a sweep operation of cyclically determining whether or not frequency synchronization has been achieved by looking at the synchronization determination signal 232.

However, even if this sweep operation is performed, since the control CPU 247 does not originally have information on the frequency position where the frequency of the second IF signal 12 is, an accurate A
Since FC operation cannot be expected, there is a possibility that it takes a very long time to perform a sweep operation in pursuit of a correct frequency forever and to establish frequency synchronization.

Further, since the determination as to whether the AFC operation is completed and frequency synchronization is established is made only by the synchronization determination signal 232 of the signal processing circuit 220, there is a possibility that a malfunction may occur if there is pseudo synchronization.

[0075]

The above-mentioned conventional satellite receiver has the following problems. (1) Since the frequency error and the drift of the first local oscillation signal are estimated by measuring the error of the center frequency of the second IF signal by the demodulation circuit, the center of the demodulation circuit is changed due to an environmental change due to a temperature change or the like. If the frequency reference value fluctuates, such a motion will be mistaken for the error of the center frequency, and the AFC operation will be performed in the direction of increasing the frequency error. I do. (2) The frequency error and drift of the first local oscillation signal are reduced by the second I
Since the error of the center frequency of the F signal is estimated by indirectly measuring the error, the AFC operation cannot be performed accurately and quickly. (3) When the digital modulation method is adopted, the demodulation circuit has a narrow error estimation range for estimating the center frequency error from the phase error, so that the error and the drift of the first local oscillation signal frequency are large. Can not estimate the error
Correction by C operation cannot be performed. (4) It is impossible to reduce the error of the AFC operation and the phase error at the same time. (5) In a conventional digital satellite receiver, other performances such as a pull-in time until a phase frequency error is minimized and a holding strength of a correction loop when C / N (signal-to-noise power ratio) is deteriorated are mutually different. There is a conflicting relationship, and the frequency pull-in range of the correction loop cannot be increased, and only a pull-in range of about several hundred KHz can be obtained. (6) In the conventional digital satellite receiver, the control CPU constantly monitors the synchronization determination signal.
A complicated program setting of the sweep operation has to be performed, in which the frequency setting signal is output step by step and the frequency is synchronized cyclically each time by checking the synchronization determination signal. (7) In the conventional digital satellite receiver, even if the sweep operation is performed, an accurate AFC operation cannot be expected, and the sweep operation is stochastically pursued forever at the correct frequency, and the frequency synchronization is established. Can be very time consuming. (8) In a conventional digital satellite receiver, there is a possibility that a malfunction may occur if there is pseudo synchronization.

An object of the present invention is to provide a satellite receiver capable of performing an accurate AFC operation without malfunctioning in an analog modulation method or a digital modulation method. It is another object of the present invention to provide a satellite receiver having a local oscillator capable of performing AFC operation accurately and reducing phase noise.

[0077]

According to a first aspect of the present invention, there is provided a satellite receiver for receiving a radio wave from a satellite and outputting the received signal as a group of received signals.
An amplifier for amplifying and outputting a received signal group output from the parabolic antenna;
A first local oscillator that outputs a local oscillation signal; a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal; A first 1 / N frequency divider for dividing the frequency by a frequency division ratio and outputting it as a 1 / N frequency-divided first local oscillation signal;
A first band-pass filter that passes only the frequency component of the frequency-divided first local oscillation signal, an output signal from the first mixer, and the 1 / N frequency-divided output from the first band-pass filter A second mixer that mixes and outputs the first local oscillation signal, and a first IF that is a difference between the received signal group and the first local oscillation signal among signals output from the second mixer. An outdoor converter comprising a signal group and a second band-pass filter that passes the 1 / N-divided first local oscillation signal and outputs the signal as an outdoor converter output signal; 1
A tuned amplifier for selecting, amplifying and outputting an IF signal group, a third mixer for mixing and outputting an output signal from the tuned amplifier and a VCO output signal, and a third mixer for outputting an output signal from the third mixer. An IF circuit that outputs a signal having a certain frequency as a second IF signal, a demodulation circuit that demodulates the second IF signal, and only the 1 / N-divided first local oscillation signal included in the outdoor converter output signal A third band-pass filter that passes and outputs the VCO output signal, and divides the VCO output signal by the same frequency division ratio as the first frequency divider to obtain a 1 / N frequency division V
A second 1 / N divider that outputs as a CO signal, and a mixture of the 1 / N divided first local oscillation signal output from the third bandpass filter and the 1 / N divided VCO signal A fourth mixer, which outputs the sum of the 1 / N-divided first local oscillation signal and the 1 / N-divided VCO signal among the signals output from the fourth mixer. A fourth band-pass filter that passes only the added local oscillation signal and outputs it as a local oscillation signal, and a programmable frequency divider that divides the added local oscillation signal by a frequency division ratio set by a programmable frequency divider setting signal and outputs the resultant signal. A reference oscillator that outputs a signal of a certain frequency as a reference signal for PLL control, a phase of a frequency reference signal output from the reference oscillator, and a signal output from the programmable frequency divider. Rank A phase comparator that outputs the phase difference as a phase error signal; a low-pass filter that converts the phase error signal output from the phase comparator into a DC voltage and outputs the DC voltage as VCO control; A VCO for generating a signal having a frequency determined by the voltage of the signal and outputting the signal as the VCO output signal; and a frequency obtained by adding a center frequency of the second IF signal to a frequency in the first IF signal group of a channel to be received is the second frequency.
And a frequency obtained by adding a frequency obtained by dividing the frequency divided by the frequency division ratio of the 1 / N frequency divider and a frequency obtained by dividing the first local oscillation signal by the frequency division ratio of the first frequency divider. A control CP for setting a value obtained by dividing the value obtained by dividing the frequency as the frequency division ratio in the programmable frequency divider by the programmable frequency divider setting signal
U and an indoor tuner composed of U.

According to the present invention, the first local oscillation signal is converted to the first 1 /
The frequency is divided by the N frequency divider and output as a 1 / N-divided first local oscillation signal from the outdoor tuner together with the first IF signal group. In the indoor tuner, the 1 / N-divided first local oscillation is performed by the third band-pass filter. The signal is taken out and the third mixer outputs V
A CO output signal is mixed with a 1 / N frequency-divided VCO signal, which is a signal obtained by dividing the CO output signal by the same frequency division ratio as the first 1 / N frequency divider, and PLL
Construct a loop. When the frequency of the first local oscillation signal fluctuates, the PLL circuit included in the indoor tuner performs an AFC operation that maintains the frequency of the second IF signal constant by generating a VCO output signal that corrects the fluctuation. .

Thus, accurate and quick AFC operation
It can be performed without being affected by the modulation method and without malfunction.

Further, the satellite receiver according to claim 2 has a first
In order to cope with a satellite receiver in which the frequency of the local oscillation signal is higher than the frequency of the received signal group, a fourth band-pass filter provides the 1 / N of the signals output from the third mixer. Only the signal of the difference component between the frequency-divided first local oscillation signal and the 1 / N frequency-divided VCO signal is passed and subtracted and output as the local oscillation signal.

According to a third aspect of the present invention, there is provided a satellite receiver for receiving a radio wave from a satellite and outputting it as a received signal group, and an amplifier for amplifying and outputting the received signal group output from the parabolic antenna. A first local oscillator that outputs a signal of a certain frequency as a first local oscillation signal, a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal, A first 1 / N divider that divides the first local oscillation signal by a certain division ratio and outputs the result as a 1 / N-divided first local oscillation signal; A first band-pass filter that passes only a frequency component of one local oscillation signal, an output signal from the first mixer, and the 1 / N-divided first local signal output from the first band-pass filter No. that mixes and outputs the oscillation signal , A first IF signal group which is a difference between the received signal group and the first local oscillation signal among the signals output from the second mixer, and the 1 / N-divided first local oscillation signal And a tunable amplifier for selecting, amplifying and outputting the first IF signal group among the outdoor converter output signals, and a second band-pass filter for passing the output signal as an outdoor converter output signal. A third mixer for mixing and outputting an output signal from the tuning amplifier and a VCO output signal, and outputting a signal having a certain frequency among output signals from the third mixer as a second IF signal And an IF circuit for performing the
A demodulation circuit for demodulating an F signal; a third band-pass filter for passing and outputting only the 1 / N-divided first local oscillation signal included in the outdoor converter output signal;
A pre-divider for dividing the CO output signal by a constant dividing ratio;
A counter circuit that measures the frequency of the 1 / N-divided first local oscillation signal output from the third band-pass filter and outputs the measurement result as a counter measurement value; A programmable frequency divider that divides a signal by a frequency division ratio set by a programmable frequency divider setting signal and outputs the divided signal;
A reference oscillator that outputs a frequency reference signal serving as a reference for L control, a phase of a frequency reference signal output from the reference oscillator is compared with a phase of a signal output from the programmable frequency divider, and the phase difference is calculated. A phase comparator that outputs a phase error signal; a low-pass filter that converts the phase error signal output from the phase comparator into a DC voltage and outputs the DC voltage as VCO control; and a signal having a frequency determined by the voltage of the VCO control signal. And a VCO for generating the output as the VCO output signal, and a division ratio obtained by adding a division ratio of the pre-divider and a division ratio of the programmable divider to the first IF signal group of a channel to be received. And the frequency obtained by adding the center frequency of the second IF signal to the frequency of the second IF signal is divided by the frequency of the frequency reference signal. When the frequency division ratio of the programmable frequency divider is set by a ramable frequency divider setting signal, and the frequency fluctuation of the 1 / N frequency-divided first local oscillation signal is detected by the counter measurement value, the frequency of the VCO output signal becomes An indoor tuner comprising a control CPU for controlling the frequency division ratio of the programmable frequency divider so as to have a frequency for correcting frequency fluctuation.

According to the satellite receiver of the fourth aspect, the indoor tuner detects the presence or absence of the 1 / N-divided first local oscillation signal output from the third band-pass filter, A detection circuit that outputs the detection result as a detection signal; and a detection circuit that is provided between the fourth band-pass filter and the programmable frequency divider. A selecting circuit that selects one of the local oscillation signals and outputs the selected signal to the programmable frequency divider, wherein the demodulation circuit determines whether a center frequency of the second IF signal is higher or lower than a set frequency. Information is output to the control CPU as an AFC signal, and the control CPU
When it indicates that there is an N-divided first local oscillation signal, the selection control signal controls the selection circuit,
After the addition, the local oscillation signal is selected and output to the programmable frequency divider.
When it indicates that there is no frequency-divided first local oscillation signal, the selection control signal controls the selection circuit,
The 1 / N frequency-divided VCO signal is selected and output to the programmable frequency divider, and the A / F using the AFC signal is selected.
Perform FC operation.

According to the present invention, the 1 / N frequency dividing first detection is performed by the detection circuit.
The presence or absence of a local oscillation signal is detected to detect whether the connected outdoor converter is of the present invention or a conventional one, and a control CPU
Is AF when a conventional outdoor converter is connected
The conventional AFC operation using the C signal is performed, and when the outdoor converter of the present invention is connected, the AFC operation using the 1 / N-divided first local oscillation signal is performed.

Therefore, the compatibility with the conventional satellite receiver can be maintained, and the transition to the new satellite receiver can be smoothly performed without affecting the conventional satellite receiver.

According to the satellite receiver of the fifth aspect, the indoor tuner detects the presence or absence of the 1 / N-divided first local oscillation signal output from the third band-pass filter, The demodulation circuit further includes a detection circuit that outputs the detection result as a detection signal, wherein the demodulation circuit outputs information as to whether the center frequency of the second IF signal is higher or lower than a set frequency to the control CPU as an AFC signal. And the control CPU determines that the detection signal is 1 / N frequency-divided first.
When the local oscillation signal is present, the AFC operation using the counter measurement value is performed, and when the detection signal indicates that the 1 / N-divided first local oscillation signal is not present, Performs an AFC operation using the AFC signal.

In the present invention, the first / N-divided first signal is detected by the detection circuit.
The presence or absence of a local oscillation signal is detected to detect whether the connected outdoor converter is of the present invention or a conventional one, and a control CPU
Is AF when a conventional outdoor converter is connected
The conventional AFC operation using the C signal is performed, and when the outdoor converter of the present invention is connected, the AFC operation using the counter measurement value is performed.

Therefore, the compatibility with the conventional satellite receiver can be maintained, and the transition to the new satellite receiver can be smoothly performed without affecting the conventional satellite receiver.

A satellite receiver according to a seventh aspect of the present invention provides a parabolic antenna for receiving radio waves from a satellite and outputting the received signal group as a received signal group, and an amplifier for amplifying and outputting the received signal group output from the parabolic antenna. A first local oscillator that outputs a signal of a certain frequency as a first local oscillation signal, a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal, A first 1 / N divider that divides the first local oscillation signal by a certain division ratio and outputs the result as a 1 / N-divided first local oscillation signal; A first band-pass filter that passes only a frequency component of one local oscillation signal, an output signal from the first mixer, and the 1 / N-divided first local signal output from the first band-pass filter No. that mixes and outputs the oscillation signal , A first IF signal group which is a difference between the received signal group and the first local oscillation signal among the signals output from the second mixer, and the 1 / N-divided first local oscillation signal And a tunable amplifier for selecting, amplifying and outputting the first IF signal group among the outdoor converter output signals, and a second band-pass filter for passing the output signal as an outdoor converter output signal. A third mixer for mixing and outputting an output signal from the tuning amplifier and a second local oscillation signal;
An IF circuit that outputs a signal having a certain frequency out of the output signals from the mixer as a second IF signal;
A demodulation circuit for demodulating an IF signal, a third band-pass filter for passing and outputting only the 1 / N-divided first local oscillation signal included in the outdoor converter output signal, a crystal oscillator, A fourth mixer that mixes the 1 / N-divided first local oscillation signal output from the band-pass filter with the signal of the crystal oscillator; and a first mixer among the signals output from the fourth mixer. A fourth band-pass filter that passes only a signal of a difference component between a / N frequency-divided first local oscillation signal and the signal of the crystal oscillator; and a second 1 / N frequency divider that outputs a first VCO output signal to the second frequency divider. A second 1 / N frequency divider that divides the frequency by the same frequency division ratio and outputs the same; a phase of the signal output from the fourth bandpass filter; and a signal output from the first 1 / N frequency divider. Compare the phase of the signal and use the phase difference as the phase error signal A first low-pass filter that converts a phase error signal output from the first phase comparator into a DC voltage, and outputs the DC voltage as VCO control; A first signal for generating a signal having a frequency determined by the voltage of the output VCO control signal and outputting the signal as the first VCO output signal;
And a programmable frequency divider for dividing and outputting the second VCO output signal at a frequency division ratio set by a programmable frequency divider setting signal, and a channel interval frequency in the received signal group divided by an integer. The frequency signal is P
A reference oscillator that outputs a frequency reference signal serving as a reference for LL control; a phase of a frequency reference signal output from the reference oscillator is compared with a phase of a signal output from the programmable frequency divider; A second phase comparator that outputs a phase error signal, and a phase error signal that is output from the second phase comparator is converted into a DC voltage,
A second low-pass filter that outputs as O control, and a second VCO that generates a signal having a frequency determined by the voltage of the VCO control signal output from the second low-pass filter and outputs the signal as the second VCO output signal A fifth mixer for mixing and outputting the first VCO output signal and the second VCO output signal; and a first VCO of signals output from the fifth mixer. A fifth bandpass filter that passes only the signal of the difference component between the output signal and the second VCO output signal and outputs the signal as the second local oscillation signal;
The center frequency of the second IF signal and the first IF signal of the channel to be received are obtained from a frequency obtained by multiplying the frequency obtained by reducing the frequency of the N-divided first local oscillation signal by the frequency division ratio of the second 1 / N frequency divider. A control C for reducing the center frequency in the group and setting a value obtained by dividing the frequency obtained as a result of the reduction by the frequency of the frequency reference signal as the frequency division ratio in the programmable frequency divider by the programmable frequency divider setting signal.
And an indoor tuner including a PU.

According to the present invention, the first local oscillation signal is converted to the first 1 /
The frequency is divided by the N frequency divider and output from the outdoor converter together with the first IF signal group. In the indoor tuner, the 1 / N frequency-divided first local oscillation signal is extracted by the third band-pass filter, and the crystal oscillator is extracted by the fourth mixer. The difference between the signal of
The frequency is multiplied by the frequency division ratio of the second frequency divider by a PLL composed of a phase comparator, a second 1 / N frequency divider, a first low-pass filter, and a first VCO. And the fifth
The second local oscillation signal is mixed with the second VCO output signal by the mixer described above, and only the difference component is used as the second local oscillation signal, so that when the frequency of the first local oscillation signal changes, the second local oscillation signal changes in reverse. Thus, the frequency of the second IF signal is kept constant.

Therefore, even if the reference frequency of the reference oscillator is set high, the accuracy of the AFC operation is not deteriorated, so that the AFC operation can be performed accurately and quickly, and the phase noise can be reduced.

Further, the satellite receiver according to the eighth aspect has the first
Since the frequency of the local oscillation signal is higher than the frequency of the received signal group, the frequency of the 1 / N-divided first local oscillation signal is higher than the frequency of the crystal oscillator, and the control CPU From the frequency obtained by subtracting the frequency of the crystal oscillator from the frequency of the 1 / N frequency-divided first local oscillation signal, and dividing the frequency by the frequency division ratio of the second 1 / N frequency divider,
The center frequency of the second IF signal and the center frequency of the channel to be received in the first IF signal group are subtracted, and a value obtained by dividing a frequency obtained as a result of the subtraction by the frequency of the frequency reference signal is used as the frequency division ratio as the programmable ratio. The programmable divider is set by the divider setting signal.

Further, the satellite receiver according to the ninth aspect has the following features.
In order to cope with a satellite receiver in which the frequency of the local oscillation signal is higher than the frequency of the received signal group, the fourth band-pass filter includes 1 / N of the signals output from the fourth mixer. Only the signal of the sum component of the first local oscillation signal and the output signal of the crystal oscillator is passed and output.

According to a tenth aspect of the present invention, in the satellite receiver, the indoor tuner detects the presence or absence of the 1 / N-divided first local oscillation signal output from the third band-pass filter, and A detection circuit that outputs a result as a detection signal; a second crystal oscillator that outputs a signal having a frequency difference between the frequency of the signal of the crystal oscillator and the frequency of the 1 / N-divided first local oscillation signal; A signal is provided between a fourth band-pass filter and the first phase comparator, and selects one of the signals from the second crystal oscillator and the fourth band-pass filter in accordance with an instruction of a selection control signal. A first selection circuit for outputting to the first phase comparator, a frequency divider for dividing a reference frequency signal from the reference oscillator by a certain division ratio, the reference oscillator and the second Between the phase comparator A second selection circuit for selecting either the reference frequency signal or the signal from the frequency divider according to an instruction of the selection control signal and outputting the selected signal to the second phase comparator; The circuit outputs information as to whether the center frequency of the second IF signal is higher or lower than a set frequency to the control CPU as an AFC signal,
When the detection signal indicates that there is a 1 / N-divided first local oscillation signal, the control CPU controls the first selection circuit by the selection control signal to control the fourth selection circuit.
And outputs the signal from the band pass filter to the first phase comparator. The second control circuit controls the second selection circuit by the selection control signal to select the reference frequency signal. And if the detection signal indicates that there is no 1 / N-divided first local oscillation signal, the first selection circuit is controlled by the selection control signal. Selecting an output signal from the second crystal oscillator and outputting it to the first phase comparator;
The second control circuit controls the second selection circuit by the selection control signal to select an output signal from the frequency divider, output the selected signal to the second phase comparator, and use the AFC signal.
Perform FC operation.

In the present invention, the first / N-divided first signal is detected by the detection circuit.
The presence or absence of a local oscillation signal is detected to detect whether the connected outdoor converter is of the present invention or a conventional one, and a control CPU
Is AF when a conventional outdoor converter is connected
The conventional AFC operation using the C signal is performed, and when the outdoor converter of the present invention is connected, the AFC operation using the 1 / N-divided first local oscillation signal is performed.

Therefore, the compatibility with the conventional satellite receiver can be maintained, and the transition to the new satellite receiver can be smoothly performed without affecting the conventional satellite receiver.

[0096] According to the satellite receiver of the eleventh aspect, the outdoor converter is provided between the first mixer and the second mixer 7 in the 1 / N-divided first local unit. There is further provided a band elimination filter for eliminating the frequency band of the oscillation signal.

The present invention uses 1 / N to transmit to indoor tuners.
This is to improve the carrier-to-noise power ratio of the divided first local oscillation signal.

Therefore, malfunction of the indoor tuner due to noise can be prevented, and the AFC operation can be further ensured.

A satellite receiver according to a twelfth aspect of the present invention provides a parabolic antenna for receiving radio waves from a satellite and outputting the same as a received signal group, and an amplifier for amplifying and outputting the received signal group output from the parabolic antenna. A first local oscillator that outputs a signal of a certain frequency as a first local oscillation signal, a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal, Divides the first local oscillation signal by a certain division ratio to obtain 1 / N
A first 1 / N frequency divider that outputs the frequency-divided first local oscillation signal, a first band-pass filter that passes only the frequency component of the 1 / N frequency-divided first local oscillation signal,
A second mixer for mixing and outputting an output signal from the mixer of (1) and the 1 / N-divided first local oscillation signal output from the first band-pass filter; and a second mixer. And a first IF signal group, which is a difference between the received signal group and the first local oscillation signal, and the 1 / N-divided first local oscillation signal, which are output as outdoor converter output signals. An outdoor converter including a second band-pass filter, a tuning amplifier for selecting, amplifying and outputting the first IF signal group among the outdoor converter output signals, and an output signal from the tuning amplifier and a PLL.
A third mixer that mixes and outputs a frequency synthesizer output signal, and an IF circuit that selects, amplifies, and outputs a signal having a certain frequency among the output signals from the third mixer as a second IF signal A quadrature demodulation circuit that performs quadrature demodulation and A / D conversion of the second IF signal and outputs the data as IQ data that is digital data on a complex plane; and IQ data output from the quadrature demodulation circuit by a frequency setting signal. A demodulation circuit that corrects the phase and frequency with the centered frequency as the center frequency and outputs the result as IQ demodulated data;
A signal processing circuit that performs signal processing on the IQ demodulated data and outputs the demodulated data as demodulated data and outputs a synchronization determination signal when synchronization is lost; and the 1 / N-divided first local unit of the outdoor converter output signal A third band-pass filter that allows only an oscillation signal to pass, and a counter circuit that measures the frequency of the 1 / N-divided first local oscillation signal output from the third band-pass filter and outputs the frequency as a counter measurement value From the counter measurement value,
An arithmetic circuit for detecting a deviation from the set frequency of the / N-divided first local oscillation signal as a frequency error, and outputting a frequency setting signal for correcting the frequency error to the demodulation circuit; A PLL frequency synthesizer that outputs the signal as the PLL frequency synthesizer signal, a control CPU that controls the output frequency of the PLL frequency synthesizer, and a tuning station that instructs the control CPU to control the PLL frequency synthesizer. An indoor tuner including an instruction unit.

In the present invention, the first local oscillation signal is converted to the first 1 /
The frequency is divided by the N frequency divider and output as a 1 / N-divided first local oscillation signal from the outdoor tuner together with the first IF signal group. In the indoor tuner, the 1 / N-divided first local oscillation is performed by the third band-pass filter. The signal is taken out and measured by a counter circuit to detect a deviation from the set frequency of the 1 / N-divided first local oscillation signal as a frequency error, and the arithmetic circuit determines the set frequency of the frequency setting signal output to the demodulation circuit by the frequency. The correction is made by the amount of the error so that the center frequency of the demodulation circuit always matches the frequency of the IQ data.

Therefore, accurate and quick AFC operation can be performed without erroneous operation without requiring complicated processing such as sweep operation.

A satellite receiver according to a thirteenth aspect of the present invention provides a parabolic antenna for receiving a radio wave from a satellite and outputting it as a received signal group, and an amplifier for amplifying and outputting the received signal group output from the parabolic antenna. A first local oscillator that outputs a signal of a certain frequency as a first local oscillation signal, a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal, Divides the first local oscillation signal by a certain division ratio to obtain 1 / N
A first 1 / N frequency divider that outputs the frequency-divided first local oscillation signal, a first band-pass filter that passes only the frequency component of the 1 / N frequency-divided first local oscillation signal,
A second mixer for mixing and outputting an output signal from the mixer of (1) and the 1 / N-divided first local oscillation signal output from the first band-pass filter; and a second mixer. And a first IF signal group, which is a difference between the received signal group and the first local oscillation signal, and the 1 / N-divided first local oscillation signal, which are output as outdoor converter output signals. An outdoor converter including a second band-pass filter, a tuning amplifier for selecting, amplifying and outputting the first IF signal group among the outdoor converter output signals, and an output signal from the tuning amplifier and a PLL.
A third mixer that mixes and outputs a frequency synthesizer output signal, and an IF circuit that selects, amplifies, and outputs a signal having a certain frequency among the output signals from the third mixer as a second IF signal And quadrature demodulation for shifting the center frequency when demodulating by the frequency error indicated by the frequency error signal and quadrature demodulating and A / D converting the second IF signal to output as IQ data which is digital data on a complex plane. Circuit, and I output from the quadrature demodulation circuit.
A demodulation circuit that corrects the phase and frequency of the Q data with a predetermined frequency as a center frequency and outputs the data as IQ demodulated data, and performs signal processing on the IQ demodulated data and outputs the demodulated data as demodulated data; A signal processing circuit that outputs a synchronization determination signal, a third bandpass filter that passes only the 1 / N-divided first local oscillation signal of the outdoor converter output signal,
The 1/3 output from the third band-pass filter
A counter circuit for measuring the frequency of the N-divided first local oscillation signal and outputting it as a counter measurement value; and a deviation from the counter measurement value to the set frequency of the 1 / N-divided first local oscillation signal as a frequency error. An arithmetic circuit for detecting and outputting the frequency error to the quadrature demodulation circuit as a frequency error signal; a PLL frequency synthesizer for outputting a signal of a set frequency as the PLL frequency synthesizer signal; and an output of the PLL frequency synthesizer A control CPU for controlling the frequency;
An indoor tuner that includes a channel selection instruction unit that instructs to control the frequency synthesizer.

According to the present invention, the first local oscillation signal is converted to the first 1 /
The frequency is divided by the N frequency divider and output as a 1 / N-divided first local oscillation signal from the outdoor tuner together with the first IF signal group. In the indoor tuner, the 1 / N-divided first local oscillation is performed by the third band-pass filter. A signal is taken out and measured by a counter circuit to detect a deviation from the set frequency of the 1 / N-divided first local oscillation signal as a frequency error, and the arithmetic circuit converts the frequency error to a quadrature demodulation circuit as a frequency error signal. The frequency is output so that the center frequency of the quadrature demodulation circuit always coincides with the frequency of the second IF signal.

Therefore, an accurate and quick AFC operation can be performed without malfunction without requiring complicated processing such as a sweep operation.

[0105]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing the configuration of a satellite receiver according to a first embodiment of the present invention, and FIG.
FIG. 4 is a signal frequency array diagram for explaining the operation of the present embodiment. The same numbers as those in FIG. 12 indicate the same components.

This embodiment comprises a parabolic antenna 1, an outdoor converter 2, and an indoor tuner 3.

The outdoor converter 2 includes an amplifier 4, a mixer 5, a first local oscillator 6, a mixer 7, a band-pass filter 8, a 1 / N frequency divider 9, a band-pass filter 1,
0.

The 1 / N frequency divider 9 outputs the first local oscillation signal 12
Is divided by a certain frequency division ratio and output as a 1 / N frequency-divided first local oscillation signal 15.

The band-pass filter 10 passes only the frequency component of the 1 / N-divided first local oscillation signal 15 of the signal output from the 1 / N divider 9 and outputs the signal.

The first mixer 7 outputs the first
The IF signal group 13 and the 1 / N-divided first local oscillation signal 15 output from the band-pass filter 10 are mixed and output.

The band-pass filter 8 passes only the first IF signal group 13 and the 1 / N-divided first local oscillation signal 15 among the signals output from the mixer 7 and outputs the signal as an outdoor converter output signal 14.

Here, the dividing ratio of the 1 / N divider 9 is N = 6.
Then, the frequency of the first local oscillation signal 12 is 10.67.
1779.666667 MH obtained by dividing 8 GHz by 6
z is the frequency of the 1 / N-divided first local oscillation signal 15,
As shown in FIG. 2, the 1 / N-divided first local oscillation signal 15 is frequency-multiplexed in the upper frequency band of the first IF signal group 13 to constitute the outdoor converter output signal 14 as a whole.

As described above, when another signal is frequency-multiplexed above the first IF signal group 13, particularly in a so-called upper local oscillation superheterodyne system in which a local oscillation signal is placed in an upper frequency band of a reception frequency band, an image is generated in an indoor tuner. There is a concern that an interference problem may occur. If the frequency of the second IF signal 40 on the indoor tuner side is 479.5 MHz in the present embodiment, the image frequency in the BS-1 is 104
The value obtained by adding twice the value of 479.5 MHz to 9.48 MHz is 2008.48 MHz, which is 131 in BS-15.
This is 2277.00 MHz, which is a value obtained by adding twice the value of 479.5 MHz to 8.00 MHz. However, these frequencies are 1 / N frequency divided 1
Since the frequency is sufficiently far from 779.666667 MHz, an image disturbance problem cannot occur.

Further, the frequency of 1779.666667 MHz of the 1 / N-divided first local oscillation signal 15 is about 46 times as much as 1318.00 MHz of BS-15 which is the highest reception frequency.
Since there is a difference of 1 MHz and the frequencies are sufficiently far apart, other interference problems, such as adjacent channel interference, cannot occur. In addition, the outdoor converter 2 in the present embodiment is different from the conventional outdoor converter only in the first IF.
Since only the frequency division multiplexing of the 1 / N-divided first local oscillation signal 15 is performed on the upper frequency band of the signal group 13, it has compatibility that can be used in combination with a conventional indoor tuner. .

The indoor tuner 3 receives the outdoor converter output signal 14 as an input signal and uses the conventional indoor tuner 5 shown in FIG.
4, the control CPU 55 is replaced with the control CPU 31, and the pre-frequency divider 56 is replaced with a 1 / N frequency divider 29, a mixer 21,
The band pass filter 22 is replaced with a band pass filter 20.

The band-pass filter 20 allows only the 1 / N-divided first local oscillation signal 15 included in the outdoor converter output signal 14 input to the indoor tuner 3 to pass and output.

The 1 / N divider 29 outputs the VCO output signal 33
Is divided by the same division ratio as the 1 / N frequency divider 9 to obtain a 1 / N frequency division V
Output as a CO signal 34.

The mixer 21 outputs a 1 / N-divided VCO signal 34
And the 1 / N-divided first local oscillation signal 15 output from the band-pass filter 20 and output.

The band-pass filter 22 outputs the 1 / N-divided first local oscillation signal 1 of the signal output from the mixer 21.
Only the signal of the sum component of the 5 and 1 / divided VCO signal 34 is passed and added and output as the local oscillation signal 35.

When the upper local oscillation method is used, the control CPU 31 sets the frequency at which the division ratio of the programmable frequency divider 24 is obtained by the programmable frequency divider setting signal 23 by the following equation (1) to the reference signal of the reference oscillator 25. Is set to be a value obtained by dividing by the frequency of 10 kHz.

F _OSC1 / N + (f _O + f _IF2 ) / N (1) where f _O is the frequency of the channel to be received in the first IF signal group 13 and f _IF2 is the frequency of the second IF signal 40 (479 .5 MHz), f _OSC1 is the first local oscillation signal 1
2 set frequency (10.6788000 GHz), N is 1
/ N is the frequency division ratio of the frequency dividers 9 and 29. Naturally, f _OSC1 / N is the frequency of the 1 / N- _divided first local oscillation signal 15.

For example, 1318.00 MH of BS-15
When selecting z, the first IF of the channel to be received
The frequency of 1318.00 MHz in the signal group 13 is 47
The frequency 1797.5 MHz obtained by adding 9.5 MHz is 1
299.583333 divided by the division ratio 6 of the / N divider 29
A frequency 2 obtained by adding 33 MHz and the frequency 1779.666667 MHz of the 1 / N-divided first local oscillation signal 15
After the addition, the local oscillation signal 35
Frequency.

Next, the AFC operation of this embodiment will be described.
Description will be made using the case where the BS-15 is selected.

First, the frequency of the first local oscillation signal 12 is accurately set to 10.678000 G without any error and without drifting.
When the frequency is 1 Hz and the frequency division ratio N of the 1 / N frequency divider 9 is N = 6, the frequency of the local oscillation signal 35 after addition becomes 20799.250,000 MHz as described above. In order to configure the PLL to be controlled at 1797.5 MHz, the frequency division ratio of the programmable frequency divider 24 is 2079.250000 MHz, which is the value obtained by dividing 20792.50000 MHz by the reference frequency 10 KHz of the reference oscillator 25.
Must be set to 25.

Here, the frequency of the first local oscillation signal 12 drifts 1.8 MHz in the negative direction due to some factor such as a temperature change or a change over time, and becomes 10.676200 GHz.
, The frequency of the 1 / N-divided first local oscillation signal 15 becomes 1779.336667 MHz, but the frequency division ratio of the programmable frequency divider 24 becomes 2 as described above.
Since 07925 is set, the frequency of the VCO output signal 33 is changed from 20792.50000 MHz to 1779.
299.8833333 minus 366667 MHz
The frequency is controlled to 1799.999998 MHz, which is six times the frequency.

This is used as the BS of the outdoor converter output signal 14.
When it is replaced with the center frequency of a −15 signal, 11.9 is obtained.
1319.800000 MHz corresponding to the difference between 9600 GHz and 10.676200 GHz is the first of BS-15.
At this point, it can be seen that the frequency error is apparently increased by 1.8 MHz due to the influence of the frequency drift of the first local oscillation signal 12.

However, in the indoor tuner 3, the BS-1 having the center frequency of 1319.800000 MHz is used.
5 signal and the frequency 1799.2 of the VCO output signal 33
Since the frequency is converted by 99998 MHz, the second I
The frequency of the F signal 40 is 479.4, which is the difference frequency between the two.
99998 MHz, and the output of the outdoor converter 2 is 1.8 MHz due to the frequency drift of the first local oscillation signal 12.
The signal that was drifting is the second IF signal 4 of the indoor tuner 3
At the frequency of 0, only 2 Hz moves, and the change of the first local oscillation signal 12 is completely corrected by the AFC operation. This is an excellent effect of the AFC operation according to the first embodiment of the present invention.

Similarly, the same applies to the case where the frequency of the first local oscillation signal 12 drifts in the plus direction. For example, if the frequency of the first local oscillation signal 12 drifts in the plus direction by 1.8 MHz, the first signal of the BS-15 is output.
The center frequency in IF signal group 13 is 1316.200.
000 MHz, but the frequency of the second IF signal 40 is 4
AFC control is performed to 79.499998 MHz. However, in practice, it is difficult to obtain such a performance because the accuracy of the reference oscillator 25 is affected.
Accuracy on the order of zero is easily and satisfactorily possible, a performance far exceeding the AFC accuracy of the prior art.

Therefore, in the satellite receiver of this embodiment, the frequency of the second IF signal 40 is set to 4 even if the frequency of the first local oscillation signal 12 changes in either the plus direction or the minus direction.
AFC operation is performed to keep high accuracy at 79.500000 MHz. Further, in this embodiment, the same A is used regardless of whether the modulation method is digital transmission or analog transmission.
FC operation can be performed.

In the same manner, BS9.4 1049.4
In the case of selecting 8 MHz, the frequency of the VCO output signal 33 is 1528.98 MHz, so that the value obtained by dividing this by 6 is 254.83 MHz and 1779.666667.
2034.494667MH which is a value obtained by adding MHz.
Since 203450 raised by dividing z by 10 KHz is set as the division ratio of the programmable frequency divider 24, the frequency of the second IF signal 40, which is the control target in this case, is calculated to be 479.5519998 MHZ, and this frequency is centered. AFC operation with high accuracy can be performed at all times, and the control error is as small as about 20 Hz.

As described above, the present embodiment does not indirectly estimate the error of the center frequency of the second IF signal 40 based on the demodulation result of the demodulation circuit 19, but Since the information is used directly, the AFC operation is performed in the direction in which the frequency error increases even when the demodulation circuit 19 fluctuates in the center frequency reference value due to an environmental change due to a temperature change or the like. It does not cause a malfunction.

In the present embodiment, the second IF signal 40 is subjected to some type of modulation regardless of whether it is digital transmission or analog transmission.
, An accurate center frequency cannot be estimated and cannot be an absolute reference. However, in this embodiment, since these signals are not used for AFC operation, accurate AFC operation is possible, and
Since this embodiment does not depend on the modulation content of the transmission signal, the present embodiment can be applied to both analog transmission and digital transmission.

In this embodiment, the demodulation circuit 19 is provided with very expensive precision components in order to minimize the drift of the center frequency reference value in preparation for an environmental change due to a temperature change or the like as in the conventional example. It is not necessary to use a standard, to adjust the reference value by very precise fine adjustment, or to carry out sufficient production control even with respect to temperature and environmental changes, so that the cost can be reduced.

Also, in the present embodiment, the original purpose of the AFC operation is to correct the error and drift of the first local oscillation signal frequency and to keep the reception frequency constant. Since the frequency information of the local oscillation signal 12 is directly used, it is possible to accurately perform the AFC operation linked with the error of the first local oscillation signal frequency and the drift in a short time, and the drift change is relatively small. Accurate and quick AFC operation is possible with high accuracy even immediately after energizing the outdoor converter power supply, which occurs in a short time.

Further, in the present embodiment, especially in the case of digital transmission or the like, the QPS for putting information in the phase direction of a signal wave is used.
Digital modulation schemes such as K and 8-phase PSK are adopted. In this case, the demodulation circuit 19 has an error estimation range of 1 to estimate the center frequency error from the phase error difference.
Although it is narrow from 0 KHz to several hundred KHz and the error of the first local oscillation signal frequency and the drifting component are large, error estimation cannot be performed. However, according to the present embodiment, the frequency of the second IF signal 40 is very precisely controlled. Demodulation circuit 19
It is not necessary to set unnecessary frequency error estimation and excessive frequency synchronization pull-in range in
It is also possible to reduce the cost.

In the present embodiment, the frequency reference signal output from the reference oscillator 25 is a signal having a frequency of 10 kHz. However, the present invention is not limited to this, and another frequency may be used.

(Second Embodiment) Next, a satellite receiver according to a second embodiment of the present invention will be described.

FIG. 3 is a block diagram showing the configuration of the second embodiment of the present invention. 1 and 8 indicate the same components.

This embodiment comprises a parabolic antenna 1, an outdoor converter 2, and an indoor tuner 37.

The indoor tuner 37 is different from the conventional indoor tuner 54 shown in FIG. 12 in that the band pass filter 20 and the counter circuit 39 are provided.
7 and the AFC signal 4 output from the demodulation circuit 19
6 is not input to the control CPU 57.

VCO 28, pre-frequency divider 38, programmable frequency divider 24, phase comparator 26, low-pass filter 2
7 operates similarly to the conventional example.

The counter circuit 39 receives the 1 / N-divided first local oscillation signal 15 output from the band-pass filter 20, measures the frequency, and outputs the measurement result as a counter measurement value 50. The counter measurement value 50 may be either serial or parallel data.

The control CPU 57 detects the frequency variation of the 1 / N-divided first local oscillation signal 15 based on the counter measurement value 50, and adjusts the frequency of the VCO output signal 33 to a frequency that corrects the frequency variation. , The frequency division ratio of the programmable frequency divider 24 is set.

(Third Embodiment) Next, a satellite receiver according to a third embodiment of the present invention will be described.

FIG. 4 is a block diagram showing the configuration of the third embodiment of the present invention.

[0147] The satellite receiver according to the present embodiment includes a parabolic antenna 1, an outdoor converter 2, and an indoor tuner 41.

The indoor tuner 41 is different from the indoor tuner 3 of the first embodiment in terms of the 1 / N-divided first local oscillation signal 1.
5 and a detection control signal 45 for detecting the presence or absence of the detection signal 47 and outputting the detection result as a detection signal 47.
A selection circuit 43 for selecting and outputting either the N-divided VCO signal 34 or the added local oscillation signal 35 is provided.
The PU 31 is replaced by a control CPU 44, and an AFC signal 46 output from the demodulation circuit 19 is input to the control CPU 44 as in the conventional example.

The control CPU 44 determines that the detection signal 47 is 1 / N
If it indicates that the frequency-divided first local oscillation signal 15 is present, the selection circuit 43 is controlled by the selection control signal 45 to select the local oscillation signal 35 after the addition and input it to the programmable frequency divider 24. And the detection signal 47 is 1 / N
When it indicates that there is no frequency-divided first local oscillation signal 15, the selection circuit 43 is controlled by the selection control signal 45 to select the 1 / N frequency-divided VCO signal 34 and send it to the programmable frequency divider 24. The AFC signal 46 is input and the AFC operation described in the conventional satellite receiver is performed.

Next, the operation of this embodiment will be described with reference to FIG.

First, if the outdoor converter connected to the indoor tuner 41 is the outdoor converter 2, the detection circuit 42 informs the control CPU 44 from the detection signal 47 that the 1 / N-divided first local oscillation signal 15 exists. Notice. Then, the control CPU 44 controls the control selection circuit 43 by the selection control signal 45, and selects and outputs the local oscillation signal 35 after the addition. Then, the control CPU 44 performs the same AFC operation as in the first embodiment of FIG.

Next, when the connected outdoor converter is the conventional outdoor converter 53, the detection circuit 47 informs the control CPU 44 from the detection signal 47 that the 1 / N-divided first local oscillation signal 15 does not exist. Notice. The control CPU 44 controls the selection circuit 43 based on this notification so that the selection circuit 43 selects the 1 / N frequency-divided VCO signal 34, and performs an AFC operation similar to that of the conventional satellite receiver by using the AFC signal 46. Do.

As a result, the indoor tuner 41 of the present embodiment automatically switches the AFC operation regardless of whether the connected outdoor converter is the conventional outdoor converter or the outdoor converter 2, thereby improving compatibility. Have.

That is, the outdoor converter 2 of this embodiment is compatible with a conventional satellite receiver, and the indoor tuner 41 of this embodiment is also compatible with a conventional satellite receiver. Therefore, in the present embodiment, it is possible to smoothly shift to a new satellite receiver without affecting the conventional satellite receiver.

(Fourth Embodiment) Next, a satellite receiver according to a fourth embodiment of the present invention will be described.

FIG. 5 is a block diagram showing a configuration of a satellite receiver according to a fourth embodiment of the present invention.

The satellite receiver of this embodiment comprises a parabolic antenna 1, an outdoor converter 2, and an indoor tuner 48.

The indoor tuner 48 detects the presence or absence of the 1 / N-divided first local oscillation signal 15 with respect to the indoor tuner 37 of the second embodiment, and outputs the detection result as a detection signal 47. 42, the control CPU 57 is replaced with a control CPU 49, and A
The FC signal 46 is input to the control CPU 49 as in the conventional example.

The control CPU 49 determines that the detection signal 47 is 1 / N
If the first local oscillation signal 15 indicates that there is a frequency division, the AFC operation similar to that of the second embodiment is performed using the counter measurement value 50, and the detection signal 47 becomes the 1 / N frequency division first first.
If it indicates that there is no local oscillation signal 15, A
The AFC operation similar to that of the conventional satellite receiver is performed by the FC signal 46.

The indoor tuner 41 of the present embodiment is compatible with the outdoor converter 53 by automatically switching the AFC operation regardless of whether the connected outdoor converter is the conventional outdoor converter 53 or the outdoor converter 2 of the present embodiment. Having.

That is, the outdoor converter 2 of this embodiment is compatible with a conventional satellite receiver, and the indoor tuner 41 of this embodiment is also compatible with a conventional satellite receiver. Therefore, in the present embodiment, similarly to the third embodiment, it is possible to smoothly shift to a new satellite receiver without affecting the conventional satellite receiver.

(Fifth Embodiment) Next, a satellite receiver according to a fifth embodiment of the present invention will be described.

FIG. 6 is a block diagram showing a configuration of a satellite receiver according to a fifth embodiment of the present invention.

In the present embodiment, the outdoor converter 2 in the first to fourth embodiments is replaced with an outdoor converter 51.

The outdoor converter 51 includes the outdoor converter 2
In contrast, a band removing filter 52 for removing the frequency band of the 1 / N-divided first local oscillation signal 15 is provided between the mixer 5 and the mixer 7.

As a result, the transmission to the indoor tuner 1
By improving the carrier-to-noise power ratio of the / N-divided first local oscillation signal 15, malfunction due to noise of the indoor tuner of the present invention is prevented, and AFC operation is further ensured.

(Sixth Embodiment) Next, a satellite receiver according to a sixth embodiment of the present invention will be described.

FIG. 7 is a signal frequency arrangement diagram for explaining a satellite receiver according to a sixth embodiment of the present invention.

Up to here, as shown in FIG. 2, the explanation has been made by arranging the 1 / N-divided first local oscillation signal 15 in the upper frequency band of the first IF signal group 13, but as shown in FIG. It is also possible to set the value of the division ratio N of the 1 / N divider 9 to, for example, 12, and to arrange the 1 / N divided first local oscillation signal 15 in the lower frequency band of the first IF signal group 13.

In this case as well, the interfering frequency relationship must be considered, but the 1 / N-divided first local oscillation signal 15 shown in FIG.
Is a frequency of 889.8833333 MHz and the second harmonic is 1779.666667 MHz, so there is no problem as described above, and the indoor tuner places a local oscillation signal in the lower frequency band of the reception frequency band, so-called lower local oscillation system. Even in the superheterodyne method, since the frequency is sufficiently distant from the image frequency, an image interference problem cannot occur.

The first to sixth embodiments have been described using the receiving system in which the first local oscillation signal 12 is arranged in the lower frequency band of the received signal group 11, as shown in FIG. However, the present invention can be applied to a receiving system in which the first local oscillation signal 12 is arranged in the upper frequency band of the received signal group 11. In this case, in each of the second and fourth embodiments of the present invention, each control C
This can be dealt with by slightly changing the PU control program. In the case of the first embodiment of the present invention and the third embodiment of the present invention, 1
The one that obtains the added local oscillation signal 35 which is the sum component of the frequency of the / N-divided first local oscillation signal 15 and the frequency of the 1 / N-divided VCO signal 34 is replaced by the 1 / N divided first local oscillation signal. This is possible by obtaining a local oscillation signal 35 after subtraction, which is a difference component between the frequency of the signal 15 and the frequency of the 1 / N frequency-divided VCO signal 34.

In the first to sixth embodiments, the case where 479.5 MHz is used as the center frequency of the second IF signal 40 has been described. However, the present invention is not limited to this. .26 MHz, 40
The present invention can be applied even when another frequency such as 2.78 MHz is used as the second IF signal frequency.

As described above, in the present invention, the first local oscillation signal 12 is frequency-divided by 1 / N, and the 1 / N frequency-divided first local oscillation signal 15
Since the configuration is such that the first IF signal group 13 is frequency-multiplexed and transmitted to the indoor tuner, the AFC operation can be performed with higher accuracy and speed than the conventional example.

(Seventh Embodiment) Next, a satellite receiver according to a seventh embodiment of the present invention will be described.

FIG. 8 is a block diagram showing a configuration of a satellite receiver according to a seventh embodiment of the present invention. FIG. 9 is a signal frequency arrangement diagram of an output signal of an outdoor converter for explaining the operation of this embodiment. FIG. 10 is a diagram for explaining the operation and effect of the present embodiment. The same numbers as those in FIG. 1 indicate the same components.

In the satellite reception of the first to sixth embodiments, the control CPU controls the frequency of the VCO output signal 33 by setting the frequency division ratio of the programmable frequency divider 24. Since the frequency of the signal 33 can be controlled only in the unit of the reference frequency of the reference oscillator 25 at a minimum, the frequency of the second IF signal 40 has a small amount of error, but a complete AFC operation cannot be performed. Even if the reference frequency is lowered, this error cannot be made zero.

When performing digital transmission, it is necessary to reduce the phase noise of the local oscillator on the receiver side because information is also modulated in the phase direction. From several hundred Hz to several MHz
In general, the method is realized by increasing the loop gain of the PLL by increasing the value. However, in order to reduce the error in the AFC operation, the reference frequency must be lowered as described above, and this is incompatible with increasing the loop gain of the PLL.

The present embodiment is for performing accurate AFC operation independent of the reference frequency of the reference oscillator and reducing the phase noise by increasing the loop gain of the PLL.

[0179] The satellite reception and parabola antenna 1, the outdoor converter 102, and the indoor tuner 103 of this embodiment are constituted.

The outdoor converter 102 is different from the outdoor converter 2 of FIG. 1 in that the 1 / N frequency divider 9 is replaced by a 1 / N frequency divider 10.
9 and the bandpass filter 8 is replaced with a bandpass filter 108.

The 1 / N frequency divider 109 divides the first local oscillation signal 12 by a frequency division ratio of 1000 and outputs it as a 1 / N divided first local oscillation signal 115. In the present embodiment, 1 / N
A description will be given of a case where 1000 is used as the frequency division ratio of the frequency divider 109. However, the present invention is not limited to this, and can be applied to a case where another frequency division ratio is used. .

The band-pass filter 108 passes only the first IF signal group 13 and the 1 / N-divided first local oscillation signal 115 among the signals output from the mixer 7 and outputs the signal as an outdoor converter output signal 114.

In the present embodiment, since the frequency division ratio N of the 1 / N divider 109 is 1000 in the present embodiment, the frequency obtained by dividing the frequency 10.678 GHz of the first local oscillation signal 12 by 1000 is 10.678 MHz. Is the frequency of the 1 / N first local oscillation signal 115, and as shown in FIG. 9, the 1 / N first local oscillation signal 11 falls in the lower frequency band of the first IF signal group 13.
5 are frequency-multiplexed to form an outdoor converter output signal 114 as a whole.

In the case where another signal is frequency-multiplexed below the first IF signal group 13, it is necessary to consider an interference problem. In this case, however, the first IF signal group 13 has 1049.
10.678, which is 48 MHz to 1318.00 MHz, which is the frequency of the 1 / N-divided first local oscillation signal 115
Since the frequency is sufficiently distant from MHz, no interference problem can occur.

Further, the outdoor converter 102 in the present embodiment is different from the conventional outdoor converter only in the first IF.
Since only the frequency multiplexing of the 1 / N-divided first local oscillation signal 115 is performed on the lower frequency band of the signal group 13, it has compatibility that can be used in combination with a conventional indoor tuner. I have.

The indoor tuner 103 includes the tuning amplifier 16.
, A mixer 17, an IF circuit 18, a demodulation circuit 19,
Band-pass filter 120, crystal oscillator 123, mixer 121, band-pass filter 122, phase comparator 124, low-pass filter 128, VCO 126
, 1 / N divider 127 and programmable divider 24
, Reference signal oscillator 125, phase comparator 26, low-pass filter 27, VCO 28, control CPU 131
, A tuning instruction unit 32, a mixer 135, and a band-pass filter 136.

The band-pass filter 120 passes and outputs only the 1 / N first local oscillation signal 115 included in the outdoor converter output signal 114.

The frequency of the crystal oscillator 123 is 12.87.
A signal of 6362 MHz is generated and output. Here, the frequency of the crystal oscillator 123 is selected and used such that the frequency input to the phase comparator 124 becomes sufficiently high. In the present embodiment, a case where 12.876362 MHz is used as the frequency of the crystal oscillator 123 will be described. However, the present invention is not limited to this, and other frequencies are used as long as the above conditions are satisfied. It can also be applied to

The mixer 121 includes the band-pass filter 12
The 1 / N first local oscillation signal 115 output from 0 and the signal output from the crystal oscillator 123 are mixed and output.

The band pass filter 122 is
1 / N 1st local oscillation signal 1 of signals output from 1
15 and only the signal of the difference component between the signals output from the crystal oscillator 123 is passed and output. As a result, the 1 / N-divided first local oscillation signal 1 having a frequency of 10.678 MHz
15 is mixed with the output signal of the crystal oscillator 123 having a frequency of 12.876362 MHz and having a frequency of 2.1983.
The band-pass filter 12 converts the signal to a 62 MHz signal.
2 output.

The phase comparator 124 compares the phase of the frequency reference signal output from the mixer 121 with the phase of the signal output from the 1 / N divider 127, and outputs the phase difference as a phase error signal. I do.

The low-pass filter 128 is provided for the phase comparator 1
Converting the phase error signal output from 24 into a DC voltage,
Output as VCO control signal.

The VCO 126 has a low-pass filter 128
A signal whose frequency is determined by the voltage of the VCO control signal output from the VCO is generated and output as the VCO output signal 145.

The 1 / N divider 127 outputs the VCO output signal 1
45 is divided at a division ratio of 1000 and output.

Here, a PLL is constituted by the phase comparator 124, the low-pass filter 128, the VCO 126, and the 1 / N divider 127, and the frequency of the signal output from the band-pass filter 122 is divided by 1 / N. Peripheral 127
VCO output signal 145 multiplied by 1000, which is the frequency division ratio of VCO.

This PLL allows the bandpass filter 12
2 is a VCO output signal 1 having a frequency of 2198.362 MHz, which is multiplied by 1000, which is the frequency division ratio of the 1 / N frequency divider 127, to output a signal having a frequency of 2.198362 MHz.
It is output as 45.

The programmable frequency divider 24 has a VCO 28
The VCO output signal 33 output from the VCO is divided by the frequency division ratio set by the programmable frequency divider setting signal 23 and output.

Reference signal oscillator 125 outputs a signal having a frequency serving as a reference for PLL control as a frequency reference signal. This frequency is an integer fraction of the channel interval 38.36 MHz of each channel in the first IF signal group 13.
In addition, the frequency is set as high as possible to reduce the phase noise. In the present embodiment, for example, this frequency is set to 1/20 of the channel interval of 38.36 MHz, and is set to 1.918 MHz. In the present embodiment, a case where 1.918 MHz is used as the frequency of the reference oscillator 125 will be described. However, the present invention is not limited to this, and even a condition that the channel interval is 38/36 MHz, which is an integer fraction, is satisfied. Then, the present invention can be applied to the case where another frequency is used.

The phase comparator 26 compares the phase of the frequency reference signal output from the reference oscillator 125 with the phase of the signal output from the programmable frequency divider 24, and outputs the phase difference as a phase error signal.

In the first to sixth embodiments, the frequency of the second IF signal 40 output from the IF circuit is 479.5.
Although the description has been made using the case of MHz, in the present embodiment, IF
Description will be made using a case where the frequency of the second IF signal 140 output from the circuit 18 is 402.78 MHz.

The control CPU 131 uses the programmable frequency divider setting signal 23 to divide the frequency of the programmable frequency divider 24 by the frequency obtained by the following equation (2) by the reference frequency of the reference oscillator 125 of 1.918 MHz. Set to be.

(F ₁₂₃ −f _OSC1 / N) × N− (f _O + f _IF2 ) (2) where f ₁₂₃ is the frequency of the output signal of the crystal oscillator 123, and is 12.876362 MHz in the present embodiment. It is. f _O is the frequency of the channel to be received in the first IF signal group, and f _IF2 is the frequency of the second IF signal 140 (4
02.78 MHz), f _0SC1 is the set frequency of the first local oscillation signal 12 (10.6788000 GHz), and N is 1 / N
The frequency division ratio of the frequency dividers 109 and 127, which is 1 in this embodiment.
000. Naturally, f _OSC1 / N is the frequency of the 1 / N- _divided first local oscillation signal 115.

For example, when BS-1 is received, the frequency division ratio of the programmable frequency divider 24 is set to 389. Thereafter, when BS-15 is received by sequentially decreasing the frequency division ratio by 20, the frequency division ratio is increased. The circumference ratio is set to 249. In this way, when receiving BS-1, the frequency of the VCO output signal 33 is 746.1 obtained by multiplying 1.918 MHz by 389.
02MHz, and when receiving BS-15, VC
The frequency of the O output signal 33 is 477.582 MHz obtained by multiplying 1.918 MHz by 249.

The mixer 135 mixes and outputs the VCO output signal 145 and the VCO output signal 33.

The band pass filter 136 is connected to the mixer 13
5 passes only the frequency component of the second local oscillation signal 147 out of the signals output from 5 and outputs.

Next, regarding the AFC operation of the present embodiment,
Description will be made using the case where the BS-15 is selected.

First, the frequency of the first local oscillation signal 12 is accurately adjusted to 10.678,000 G without any error and without drifting.
Hz, the VCO output signal 1
The frequency of 45 becomes 2198.362 MHz. Then, the control CPU 131 sets the frequency division ratio of the programmable frequency divider 24 to 249 via the programmable frequency divider 23, so that the frequency of the VCO output signal 33 is 477.58.
MHz. Then, the second local oscillation signal 147 having a frequency of 1720.78 MHz can be obtained by mixing only in the mixer 135 and passing only the difference component in the band pass filter 136. Then, the signal is mixed with the signal of BS-15 having the frequency of 1318 MHz by the mixer 17 to obtain a difference component, thereby obtaining the second signal having the frequency of 402.78 MHz.
An IF signal 1140 is obtained.

When BS-1 is received, the frequency division ratio of programmable frequency divider 24 is set to 389.
The frequency of the CO output signal 33 is 746.102 MHz. Then, the second local oscillation signal 147 having a frequency of 1452.26 MHz can be obtained by mixing only in the mixer 135 and passing only the difference component in the band pass filter 136. The frequency is set to 10 by the mixer 17.
The second IF signal 1140 having a frequency of 402.78 MHz is obtained by mixing with the BS-1 signal of 49.48 MHz and taking the difference component.

Here, the frequency of the first local oscillation signal 12 drifts by 1.5 MHz in the positive direction, for example, to 10.679500 G
Hz, it becomes 1 when receiving BS-15.
1316.5 GHz, which is the difference between 0.679500 GHz and 11.99600 GHz, is the outdoor converter output signal 1
14, the frequency in the first IF signal group 13 and the first
The first IF signal group 13 corresponds to the local oscillation signal 12 drifting.
Will also drift.

However, since the frequency of the first local oscillation signal 12 is 10.679500 GHz, the frequency of the 1 / N-divided first local oscillation signal 115 is 10.679500 GHz.
The frequency of the VCO output signal 145 is 2.19 because the difference frequency between 2. MHz and 12.876362 MHz, 2.19662 MHz, is the reference frequency of the phase comparator 124.
2196.862000 which multiplied 862MHz by 1000
MHz is obtained.

Here, when the difference frequency between the VCO output signal 145 having a frequency of 2196.62 MHz and the VCO output signal 33 having a frequency of 477.582 MHz is extracted by the mixer 135 and the band-pass filter 136, the frequency 171 is obtained.
A second local oscillation signal 147 of 9.28 MHz is obtained.
At this stage, the first local oscillation signal 12 is set to 1.
By drifting at 5 MHz Hz, the first local oscillation signal 1
47 indicates a change of 1.5 MHz in the minus direction.

Then, when the difference frequency between the second local oscillation signal 147 having a frequency of 1719.28 MHz and the BS-15 signal having a frequency of 1316.5 MHz in the first IF signal group 13 is obtained, a second IF signal 140 having a frequency of 402.78 MHz is obtained. Can be Thus, even if the first local oscillation signal 12 drifts by 1.5 MHz in the plus direction, the second I
It can be seen that the frequency of the F signal 140 is completely maintained at 402.78 MHz.

Further, in the satellite receiver of the present embodiment, the second local oscillation signal 12 is similarly generated regardless of whether the frequency of the first local oscillation signal 12 changes in either the plus direction or the minus direction.
An AFC operation for maintaining the frequency of the IF signal 40 at 402.78 MHz with high accuracy is performed. Similarly, when receiving a channel other than BS-15, the second I
AF that keeps the frequency of F signal 140 at 402.78 MHz
C operation can be performed. Further, in the present embodiment, the same AFC operation can be performed regardless of whether the modulation method is digital transmission or analog transmission.

However, since the frequency accuracy of the reference oscillator 125 and the crystal oscillator 123 is actually affected, it is difficult to obtain the performance of the above calculation. Since mass production is possible at a low cost, it is possible to easily produce a satellite receiver with AFC control accuracy of about 20 / million or less, which is far higher than the AFC accuracy of a conventional satellite receiver. Accuracy performance can be obtained.

FIG. 10 is a signal frequency arrangement diagram for explaining the operation and effect of the present embodiment. As can be seen from FIG. 10, the 1 / N-divided first local oscillation signal 1
15 frequency 10.678 MHz, second IF signal 140
402.78 MHz, the frequency of the VCO output signal 33 from 477.582 MHz to 746.102 MHz,
From the first IF signal group 13 of 1049.48 MHz to 1
318.00 MHz, 1 which is the second local oscillation signal 147
The 452.26 MHz to 1720.78 MHz, and the VCO output signal 145, 2198.362 MHz, do not overlap with each other in their frequency domain, and the image frequencies 1855.04 to 2123.56.
Since it does not overlap with MHz, no interference problem occurs in this embodiment.

(Eighth Embodiment) Next, a satellite receiver according to an eighth embodiment of the present invention will be described.

FIG. 11 is a block diagram showing the configuration of the satellite receiver according to the eighth embodiment of the present invention.

The satellite receiver of this embodiment comprises a parabolic antenna 1, an outdoor converter 102, and an indoor tuner 13.
And 8.

[0219] The indoor tuner 138 is provided with a detection circuit 142, a crystal oscillator 143, a frequency divider 145, and selection circuits 141 and 144 with respect to the indoor tuner 103 in the seventh embodiment of FIG. The control CPU 131 is replaced by a control CPU 132, and the AFC signal 46 output from the demodulation circuit 19 is changed to the control CPU 13 as in the conventional example.
2 is input.

The crystal oscillator 143 generates and outputs a signal having a frequency of 2.198362 MHz which is a difference between the frequency of the crystal oscillator 123 and the frequency of the 1 / N-divided first local oscillation signal 115.

The frequency divider 145 frequency-divides the reference signal from the reference oscillator 125 by a certain frequency division ratio and outputs the result.

The detection circuit 142 detects the presence / absence of the 1 / N-divided first local oscillation signal 115, and outputs the detection result as the detection signal 62.

The selection circuit 141 selects and outputs either the reference signal of the reference oscillator 125 or the output signal of the frequency divider 145 according to the selection control signal 161.

The selection circuit 144 selects and outputs either the output signal from the band-pass filter 122 or the output signal from the crystal oscillator 143 according to the selection control signal 160. When the detection signal 62 indicates that the 1 / N-divided first local oscillation signal 115 is present, the control CPU 132 controls the selection circuit 141 with the selection control signal 161 and outputs the reference signal from the reference oscillator 125. Is selected and input to the phase comparator 26, and the selection circuit 144 is controlled by the selection control signal 160 so that the bandpass filter 12
2 is selected and input to the phase comparator 124, and the same operation as that described in the seventh embodiment is performed.

Then, the control CPU 132 outputs the detection signal 6
When 2 indicates that there is no 1 / N frequency-divided first local oscillation signal 115, the selection circuit 141 is controlled by the selection control signal 161 to select the output signal from the frequency divider 145 and to perform phase comparison. Input to the device 26, and the selection control signal 1
60 controls the selection circuit 144 to control the crystal oscillator 14
3 is selected and input to the phase comparator 124, and AFC control using the AFC signal 46 is performed.

In the seventh and eighth embodiments, FIG.
3, the first local oscillation signal 12 is arranged in the lower frequency band of the received signal group 11 from the satellite, but the first local oscillation signal 12 is arranged in the upper frequency band of the received signal group 11 from the satellite. The present invention can correspond to a receiving system in which the local oscillation signal 12 is arranged. In this case, 1 / N is set by the mixer 121 and the bandpass filter 122.
The frequency difference component between the frequency-divided first local oscillation signal 115 and the crystal oscillator 123 is obtained such that the frequency of the 1 / N frequency-divided first local oscillation signal 115 is higher than the frequency of the crystal oscillator 123. This can be dealt with by making a selection or by taking the sum component of both frequencies.

In the seventh and eighth embodiments,
402.78M as the center frequency of the second IF signal 140
However, the present invention is not limited to this case.
The present invention can be applied to the case where another frequency such as z, 479.5 MHz is used as the second IF signal frequency.

In the seventh and eighth embodiments, if the outdoor converter 102 is provided with a band removing filter in the same manner as in the fifth embodiment, the same effect as in the fifth embodiment can be obtained. .

The various frequencies, frequency division ratios and the like used in the first to eighth embodiments are used for describing the present invention, and the present invention is limited to these frequencies, frequency division ratios and the like. The present invention can be similarly applied to other frequencies, frequency division ratios, and the like.

(Ninth Embodiment) Next, a digital satellite receiver according to a ninth embodiment of the present invention will be described.

FIG. 12 is a block diagram showing a configuration of a digital satellite receiver according to a ninth embodiment of the present invention.

In this embodiment, as shown in FIG. 12, a parabolic antenna 1, an outdoor converter 2, and an indoor tuner 2 are provided.
03. The same numbers as those in FIG. 20 indicate the same components.

The outdoor converter 2 includes an amplifier 4, a mixer 5, a first local oscillator 6, a mixer 7, a band-pass filter 8, a 1 / N frequency divider 9, a band-pass filter 1,
0, and has a configuration similar to that of the outdoor converter 2 in the first embodiment of FIG. 1 described above.

The indoor tuner 203 includes the tuning amplifier 21
5, mixer 216, IF circuit 217, quadrature demodulator 21
8, demodulation circuit 219, signal processing circuit 220, PLL frequency synthesizer 222, control CPU 223, tuning instruction unit 32, bandpass filter 20, counter circuit 39, arithmetic circuit (CPU: Central Processing)
(Unit) 221.

The indoor tuner 203 in the present embodiment
Is provided with a bandpass filter 20 and a counter circuit 39 for an indoor tuner 245 in the conventional digital satellite receiver shown in FIG.
U) 221.

Bandpass filter 20, counter circuit 3
9 is similar to that described in FIG.
The band-pass filter 20 outputs the outdoor converter output signal 1
4, and extracts and outputs only the 1 / N-divided first local oscillation signal 15. The counter circuit 39 calculates 1 / N
The frequency of the frequency-divided first local oscillation signal 15 is measured, and the measured value is used as a counter measured value 50 by an arithmetic circuit (CPU) 2.
21 is output.

The arithmetic circuit (CPU) 221 monitors the synchronization state of the signal processing circuit 220 based on the synchronization determination signal 232 and, based on the counter measurement value 50, deviates from the set frequency of the 1 / N-divided first local oscillation signal 15. Is detected as a frequency error, and the frequency control (AFC) is performed by outputting a frequency setting signal 231 to the demodulation circuit 219 to correct the frequency error.

Since the arithmetic circuit (CPU) 221 can easily and reliably know the frequency error by calculating the counter measurement value 50, the demodulation circuit 219 sets the frequency setting corresponding to the obtained frequency error. Signal 23
1 can be output and reliable frequency control (AFC)
Can be performed, and it is not necessary to perform a complicated operation such as a sweep operation.

Further, since the arithmetic circuit (CPU) 221 does not require a complicated operation as in the conventional example, it can be easily constituted by a CPU or a hardware logic circuit. It can also be used as an alarm.

(Tenth Embodiment) Next, a tenth embodiment of the present invention will be described.
A digital satellite receiver according to an embodiment will be described.

FIG. 13 is a block diagram showing a configuration of a digital satellite receiver according to a tenth embodiment of the present invention, and FIG. 14 is a block diagram showing a configuration of a quadrature demodulation circuit 234 in FIG. In this embodiment, as shown in FIG. 13, a parabolic antenna 1, an outdoor converter 2, and an indoor tuner 23 are provided.
And 3.

The frequency arrangement of the outdoor converter output signal 14 in this embodiment is as shown in FIG. 15, which is the same as in the ninth embodiment.

This embodiment differs from the ninth embodiment shown in FIG. 12 in that the indoor tuner 203 is replaced with an indoor tuner 233.

An indoor tuner 233 is different from the indoor tuner 203 in FIG.
And the quadrature demodulation circuit 218 is replaced with the quadrature demodulation circuit 234.
And the arithmetic circuit (CPU) 221 is replaced with the arithmetic circuit (C
PU) 236.

The demodulation circuit 235 outputs the frequency setting signal 231
, And the same operation as the demodulation circuit 219 is performed except that a predetermined frequency is set as the center frequency.

An arithmetic circuit (CPU) 236 detects a deviation from the set frequency of the 1 / N-divided first local oscillation signal 15 from the counter measurement value 50 as a frequency error, and outputs the frequency error as a frequency error signal 237. Otherwise, the same operation as the arithmetic circuit (CPU) 221 is performed.

The orthogonal demodulation circuit 234 is obtained by replacing the fixed oscillator 254 with a voltage controlled oscillator 243 in the orthogonal demodulation circuit 218 shown in FIG. Voltage controlled oscillator 24
3 controls such that the frequency of the signal output by the frequency indicated by the frequency error signal 237 is shifted.

The quadrature demodulation circuit 234 generates the frequency error signal 2
The same operation as that of the quadrature demodulation circuit 218 is performed except that the frequency of the voltage control oscillator 243 is controlled by 37.

In this embodiment, the arithmetic circuit (CPU) 23
6 can easily and surely know the frequency error by calculating using the counter measurement value 50, so that the quadrature demodulation circuit 234 receives the obtained frequency error signal 2
The frequency control is performed by outputting 37.

(Eleventh Embodiment) The configuration of an eleventh embodiment of the present invention is the same as that of FIG. 12, and by setting the division ratio of the 1 / N divider 9 to another value, the first IF signal In the lower frequency band of the group 13, the 1 / N-divided first local oscillation signal 15
Are different from those of the ninth embodiment only in that the outdoor converter output signal 14 is arranged in such a way as to be arranged. FIG. 16 shows a frequency array in this case.

(Twelfth Embodiment) The configuration of a twelfth embodiment of the present invention is the same as that of FIG. 13, and by setting the division ratio in the 1 / N divider 9 to another value, the first IF signal In the lower frequency band of the group 13, the 1 / N-divided first local oscillation signal 15
, And the operation is the same as that of the tenth embodiment. FIG. 16 shows a frequency array in this case.

As described above, in the ninth to twelfth embodiments, the first local oscillation signal 12 is frequency-divided by 1 / N to form a 1 / N-divided first local oscillation signal 15 above the first IF signal group 13. Since the frequency band or the lower frequency band is frequency-multiplexed and transmitted to the indoor tuner, a digital satellite receiver with AFC operation with higher accuracy and reliability than the conventional example can be realized.

[0253]

As described above, the present invention has the following effects. (1) Since the AFC operation is performed by measuring a signal obtained by dividing the frequency of the first local oscillation signal with an indoor tuner, an accurate and quick AFC operation is erroneously performed without being affected by a modulation method of a transmission signal. Can be performed without the use of (2) Since the outdoor converter of the present invention is compatible with the conventional outdoor converter, the transition from the conventional satellite receiver to the satellite receiver of the present invention can be performed smoothly. (3) In the invention according to claims 4, 5, 6, and 10, the indoor cotuner is compatible with the conventional indoor tuner, so that the transition from the conventional satellite receiver to the satellite receiver of the present invention is performed smoothly. be able to. (4) According to the seventh, eighth, and ninth aspects, the AFC operation can be performed more accurately, and the loop gain of the PLL can be increased to reduce the phase noise of the second local oscillation signal of the indoor tuner. (5) According to the eleventh aspect, by improving the carrier-to-noise power ratio of the 1 / N-divided first local oscillation signal transmitted from the outdoor tuner to the indoor tuner, malfunction due to noise in the indoor tuner is prevented. , AFC operation can be further ensured. (6) In the invention according to claims 12 to 17, it is not necessary to increase the frequency pull-in range of the frequency correction loop, and a sufficient AFC operation can be performed even in the pull-in range of about several hundred KHz. , And other performances such as the holding strength of the correction loop when the C / N (signal-to-noise power ratio) deteriorates. (7) In the invention according to claims 12 to 17, the control CPU constantly monitors the synchronization determination signal, and when synchronization is lost, outputs the frequency setting signal in small steps in a stepwise manner.
In each case, there is no need to make a complicated sweep operation program setting that cyclically checks whether or not frequency synchronization has been achieved by looking at the synchronization determination signal. (8) In the invention according to claims 12 to 17, an accurate AFC
Operation is possible, and there is no case where a sweep operation is performed forever in pursuit of a correct frequency, and it takes a very long time to establish frequency synchronization. (9) According to the inventions described in claims 12 to 17, there is no possibility of malfunction even if there is pseudo synchronization.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a satellite receiver according to a first embodiment of the present invention.

FIG. 2 is a signal frequency arrangement diagram for explaining an operation of the satellite receiver of FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of a satellite receiver according to a second embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a satellite receiver according to a third embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a satellite receiver according to a fourth embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a satellite receiver according to a fifth embodiment of the present invention.

FIG. 7 is a signal frequency arrangement diagram for explaining a satellite receiver according to a sixth embodiment of the present invention.

FIG. 8 is a block diagram illustrating a configuration of a satellite receiver according to a seventh embodiment of the present invention.

FIG. 9 is a signal frequency arrangement diagram for explaining the operation of the satellite receiver in FIG. 8;

FIG. 10 is a signal frequency arrangement diagram for explaining the operation and effect of the satellite receiver of FIG. 8;

FIG. 11 is a block diagram showing a configuration of a satellite receiver according to an eighth embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of a digital satellite receiver according to a ninth embodiment of the present invention.

FIG. 13 is a block diagram showing a configuration of a digital satellite receiver according to a tenth embodiment of the present invention.

14 is a detailed block diagram of a quadrature demodulation circuit 234 in FIG.

FIG. 15 is a frequency array diagram of the digital satellite receiver according to the ninth and tenth embodiments of the present invention.

FIG. 16 is a frequency array diagram of the digital satellite receiver according to the eleventh and twelfth embodiments of the present invention.

FIG. 17 is a block diagram showing a configuration of a conventional satellite receiver.

FIG. 18 is a signal frequency arrangement diagram for explaining a relationship between a received signal group 11 and a first local oscillation signal 12.

19 is a signal frequency arrangement diagram of the first IF signal group 13. FIG.

FIG. 20 is a block diagram showing a configuration of a conventional digital satellite receiver.

21 is a detailed block diagram of a quadrature demodulation circuit 218 of the conventional digital satellite receiver of FIG.

FIG. 22 is a detailed block diagram of a demodulation circuit 219 of the conventional digital satellite receiver of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Parabolic antenna 2 Outdoor converter 3 Indoor tuner 4 Amplifier 5 Mixer 6 1st local oscillator 7 Mixer 8 Bandpass filter 9 1 / N frequency divider 10 Bandpass filter 11 Received signal group 12 1st local oscillation signal 13 1st IF Signal group 14 Outdoor converter output signal 15 1 / N-divided first local oscillation signal 16 Tuning amplifier 17 Mixer 18 IF circuit 19 Demodulation circuit 20 Bandpass filter 21 Mixer 22 Bandpass filter 23 Programmable frequency divider setting signal 24 Programmable Frequency divider 25 Reference oscillator 26 Phase comparator 27 Low-pass filter 28 VCO 29 1 / N frequency divider 30 VCO control signal 31 Control CPU 32 Tuning instruction unit 33 VCO output signal 34 1 / N frequency-divided VCO signal 35 Local unit after addition Oscillation signal 36 Demodulation output 37 Indoor tu Na 38 Pre-frequency divider 39 Counter circuit 40 Second IF signal 41 Indoor tuner 42 Detection circuit 43 Selection circuit 44 Control CPU 45 Selection control signal 46 AFC signal 47 Detection signal 48 Indoor tuner 49 Control CPU 50 Counter measurement value 51 Outdoor converter 52 Band removal filter 53 Outdoor converter 54 Indoor tuner 55 Control CPU 56 Pre-frequency divider 57 Control CPU 58 Bandpass filter 62 Detection signal 102 Outdoor converter 103 Indoor tuner 108 Bandpass filter 109 1 / N frequency divider 114 Outdoor converter output signal 115 1 / N-divided first local oscillation signal 120 band-pass filter 121 mixer 122 band-pass filter 123 crystal oscillator 124 phase comparator 125 reference oscillator 126 VCO 127 1 / N Device 128 low-pass filter 131 control CPU 135 mixer 136 band-pass filter 138 indoor tuner 140 second IF signal 141 selection circuit 142 detection circuit 143 crystal oscillator 144 selection circuit 145 frequency divider 147 second local oscillation signal 160, 161 selection control signal 203 Indoor tuner 215 Tuning amplifier 216 Mixer 217 IF circuit 218 Quadrature demodulation circuit 219 Demodulation circuit 220 Signal processing circuit 221 Operation circuit (CPU) 222 PLL frequency synthesizer 223 Control CPU 227 Second IF signal 228 IQ data 229 IQ demodulation data 231 Frequency setting signal 232 Synchronization determination signal 233 Indoor tuner 234 Quadrature demodulation circuit 235 Demodulation circuit 236 Operation circuit (CPU) 237 Frequency error signal 238 Multiplier 239 Multiplication 240 A / D converter 241 A / D converter 242 90-degree phase shifter 243 Voltage controlled oscillator 245 Indoor tuner 246 Bandpass filter 247 Control CPU 248 Complex multiplier 249 Roll-off filter 250 NCO 251 Digital loop filter 252 Phase frequency detection 253 Sin / Cos signal 254 Fixed oscillator

Claims (17)

[Claims] 1. A parabolic antenna that receives radio waves from a satellite and outputs the received signal group as a received signal group, an amplifier that amplifies and outputs a received signal group output from the parabolic antenna, and a signal having a certain frequency. 1
A first local oscillator that outputs a local oscillation signal; a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal; A first 1 / N frequency divider for dividing the frequency by a frequency division ratio and outputting it as a 1 / N frequency-divided first local oscillation signal;
A first band-pass filter that passes only the frequency component of the frequency-divided first local oscillation signal, an output signal from the first mixer, and the 1 / N frequency-divided output from the first band-pass filter A second mixer that mixes and outputs the first local oscillation signal, and a first IF that is a difference between the received signal group and the first local oscillation signal among signals output from the second mixer. An outdoor converter including a signal group and a second band-pass filter that passes the 1 / N-divided first local oscillation signal and outputs the signal as an outdoor converter output signal; A tuned amplifier for selecting, amplifying and outputting one IF signal group, a third mixer for mixing and outputting an output signal from the tuned amplifier and a VCO output signal, and a third mixer for outputting an output signal from the third mixer; My house An IF circuit for outputting a signal having a certain frequency as a second IF signal; a demodulation circuit for demodulating the second IF signal;
A third band-pass filter that passes and outputs only the N-divided first local oscillation signal, and outputs the VCO output signal to the first
A second 1 / N frequency divider that divides the frequency by the same frequency division ratio as that of the frequency divider and outputs it as a 1 / N frequency-divided VCO signal; A fourth mixer for mixing and outputting the divided first local oscillation signal and the 1 / N frequency-divided VCO signal, and the 1 / N frequency division of the signals output from the fourth mixer; The first local oscillation signal and the 1
A fourth bandpass filter that passes only the sum component signal of the / N-divided VCO signal and outputs it as a local oscillation signal after addition, and divides the added local oscillation signal by a programmable frequency divider setting signal A programmable frequency divider that divides and outputs a signal at a certain frequency
A reference oscillator that outputs a frequency reference signal serving as a reference for LL control; a phase of a frequency reference signal output from the reference oscillator is compared with a phase of a signal output from the programmable frequency divider; A phase comparator that outputs a phase error signal; a low-pass filter that converts the phase error signal output from the phase comparator into a DC voltage and outputs the DC voltage as VCO control; and a signal having a frequency determined by the voltage of the VCO control signal. To generate the VCO
A VCO to be output as an output signal, and a second IF to a frequency of the channel to be received in the first IF signal group.
The frequency obtained by adding the center frequency of the signal is the second 1 / N
The frequency obtained by adding the frequency divided by the frequency division ratio of the frequency divider and the frequency obtained by dividing the first local oscillation signal by the frequency division ratio of the first frequency divider was divided by the frequency of the frequency reference signal. An indoor tuner comprising: a control CPU for setting a value as a frequency division ratio in the programmable frequency divider by the programmable frequency divider setting signal. 2. A parabolic antenna that receives a radio wave from a satellite and outputs the received signal group as a received signal group; an amplifier that amplifies and outputs a received signal group output from the parabolic antenna; 1
A first local oscillator that outputs a local oscillation signal; a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal; A first 1 / N frequency divider for dividing the frequency by a frequency division ratio and outputting it as a 1 / N frequency-divided first local oscillation signal;
A first band-pass filter that passes only the frequency component of the frequency-divided first local oscillation signal, an output signal from the first mixer, and the 1 / N frequency-divided output from the first band-pass filter A second mixer that mixes and outputs the first local oscillation signal, and a first IF that is a difference between the received signal group and the first local oscillation signal among signals output from the second mixer. An outdoor converter including a signal group and a second band-pass filter that passes the 1 / N-divided first local oscillation signal and outputs the signal as an outdoor converter output signal; A tuned amplifier for selecting, amplifying and outputting one IF signal group, a third mixer for mixing and outputting an output signal from the tuned amplifier and a VCO output signal, and a third mixer for outputting an output signal from the third mixer; My house An IF circuit for outputting a signal having a certain frequency as a second IF signal; a demodulation circuit for demodulating the second IF signal;
A third band-pass filter that passes and outputs only the N-divided first local oscillation signal, and outputs the VCO output signal to the first
A second 1 / N frequency divider that divides the frequency by the same frequency division ratio as that of the frequency divider and outputs it as a 1 / N frequency-divided VCO signal; A fourth mixer for mixing and outputting the divided first local oscillation signal and the 1 / N frequency-divided VCO signal, and the 1 / N frequency division of the signals output from the fourth mixer; The first local oscillation signal and the 1
A fourth band-pass filter that passes only the signal of the difference component of the / N-divided VCO signal and outputs the subtracted local oscillation signal as a local oscillation signal, and divides the subtracted local oscillation signal by a programmable frequency divider setting signal A programmable frequency divider that divides and outputs a signal at a certain frequency
A reference oscillator that outputs a frequency reference signal serving as a reference for LL control; a phase of a frequency reference signal output from the reference oscillator is compared with a phase of a signal output from the programmable frequency divider; A phase comparator that outputs a phase error signal; a low-pass filter that converts the phase error signal output from the phase comparator into a DC voltage and outputs the DC voltage as VCO control; and a signal having a frequency determined by the voltage of the VCO control signal. To generate the VCO
A VCO to be output as an output signal, and a frequency of the channel to be received in the first IF signal group to the second IF
The frequency obtained by adding the center frequency of the signal is the second 1 / N
The frequency obtained by subtracting the frequency divided by the frequency division ratio of the frequency divider and the frequency obtained by dividing the first local oscillation signal by the frequency division ratio of the first frequency divider was divided by the frequency of the frequency reference signal. An indoor tuner comprising: a control CPU that sets a value as a frequency division ratio in the programmable frequency divider by the programmable frequency divider setting signal. 3. A parabolic antenna which receives a radio wave from a satellite and outputs it as a received signal group, an amplifier which amplifies and outputs a received signal group output from the parabolic antenna, and a signal having a certain frequency. 1
A first local oscillator that outputs a local oscillation signal; a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal; A first 1 / N frequency divider for dividing the frequency by a frequency division ratio and outputting it as a 1 / N frequency-divided first local oscillation signal;
A first band-pass filter that passes only the frequency component of the frequency-divided first local oscillation signal, an output signal from the first mixer, and the 1 / N frequency-divided output from the first band-pass filter A second mixer that mixes and outputs the first local oscillation signal, and a first IF that is a difference between the received signal group and the first local oscillation signal among signals output from the second mixer. An outdoor converter including a signal group and a second band-pass filter that passes the 1 / N-divided first local oscillation signal and outputs the signal as an outdoor converter output signal; A tuned amplifier for selecting, amplifying and outputting one IF signal group, a third mixer for mixing and outputting an output signal from the tuned amplifier and a VCO output signal, and a third mixer for outputting an output signal from the third mixer; My house An IF circuit for outputting a signal having a certain frequency as a second IF signal; a demodulation circuit for demodulating the second IF signal;
A third bandpass filter that passes and outputs only the N-divided first local oscillation signal, a pre-divider that divides the VCO output signal at a constant frequency division ratio, and a third bandpass filter. A counter circuit for measuring the frequency of the output 1 / N-divided first local oscillation signal and outputting the measurement result as a counter measurement value, and a signal output from the pre-divider as a programmable frequency divider setting signal A programmable frequency divider that divides and outputs the frequency at the division ratio set by
A reference oscillator that outputs a signal of a certain frequency as a frequency reference signal serving as a reference for PLL control; and a phase of a frequency reference signal output from the reference oscillator and a phase of a signal output from the programmable frequency divider. A phase comparator for comparing and outputting the phase difference as a phase error signal;
A low-pass filter that converts a phase error signal output from the phase comparator into a DC voltage and outputs the DC voltage as VCO control, and a VP that generates a signal having a frequency determined by the voltage of the VCO control signal and outputs the signal as the VCO output signal
CO and the frequency division ratio of the frequency division ratio of the pre-frequency divider and the frequency division ratio of the programmable frequency divider are equal to the frequency of the channel to be received in the first IF signal group.
The frequency division ratio of the programmable frequency divider is set by the programmable frequency divider setting signal so as to be a value obtained by dividing the frequency obtained by adding the center frequency of the IF signal by the frequency of the frequency reference signal. 1 / N
When the frequency fluctuation of the divided first local oscillation signal is detected,
An indoor tuner comprising: a control CPU for controlling a frequency division ratio of the programmable frequency divider so that the frequency of the CO output signal becomes a frequency for correcting the frequency variation; . 4. The indoor tuner, wherein the 1/3 output from the third band-pass filter is
A detection circuit for detecting the presence or absence of the N-divided first local oscillation signal and outputting the detection result as a detection signal; and a selection control signal provided between the fourth band-pass filter and the programmable frequency divider. A selecting circuit for selecting either the 1 / N frequency-divided VCO signal or the added local oscillation signal in accordance with the instruction and outputting the selected signal to the programmable frequency divider, wherein the demodulation circuit includes the second IF signal Information as to whether the center frequency is higher or lower than the set frequency is output to the control CPU as an AFC signal, and the control CPU determines that the detection signal has a 1 / N-divided first local oscillation signal. Indicates that the selection control signal controls the selection circuit to select the added local oscillation signal and output it to the programmable frequency divider, and the detection signal When the identification information indicates that the 1 / N frequency division first local oscillation signal is not, and controls the selection circuit by the selection control signal, the 1 / N frequency division V
The satellite receiver according to claim 1, wherein a CO signal is selected and output to the programmable frequency divider, and an AFC operation using the AFC signal is performed. 5. The indoor tuner according to claim 1, wherein the 1/3 output from the third band-pass filter is
A detection circuit for detecting the presence or absence of the N-divided first local oscillation signal and outputting the detection result as a detection signal; and a selection control signal provided between the fourth band-pass filter and the programmable frequency divider. A selecting circuit for selecting either the 1 / N frequency-divided VCO signal or the subtracted local oscillation signal in accordance with the instruction and outputting the selected signal to the programmable frequency divider. Information as to whether the center frequency is higher or lower than the set frequency is output to the control CPU as an AFC signal, and the control CPU determines that the detection signal has a 1 / N-divided first local oscillation signal. In the case of indicating, the selection control signal controls the selection circuit, selects the local oscillation signal after the subtraction, and outputs it to the programmable frequency divider, the detection signal When the identification information indicates that the 1 / N frequency division first local oscillation signal is not, and controls the selection circuit by the selection control signal, the 1 / N frequency division V
The satellite receiver according to claim 2, wherein a CO signal is selected and output to the programmable frequency divider, and an AFC operation using the AFC signal is performed. 6. The indoor tuner according to claim 1, wherein the 1/3 output from the third band-pass filter is
A detection circuit that detects the presence or absence of the N-divided first local oscillation signal and outputs the detection result as a detection signal, wherein the demodulation circuit determines whether a center frequency of the second IF signal is higher than a set frequency. Low information as an AFC signal to the control CPU, and the control CPU
If the detection signal indicates that there is a 1 / N-divided first local oscillation signal, A using the counter measurement value
If the FC operation is performed and the detection signal indicates that there is no 1 / N-divided first local oscillation signal, the AF
The satellite receiver according to claim 3, wherein the satellite receiver performs an AFC operation using the C signal. 7. A parabolic antenna that receives a radio wave from a satellite and outputs the received signal group as a received signal group, an amplifier that amplifies and outputs the received signal group output from the parabolic antenna, and a signal having a certain frequency. 1
A first local oscillator that outputs a local oscillation signal; a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal; A first 1 / N frequency divider for dividing the frequency by a frequency division ratio and outputting it as a 1 / N frequency-divided first local oscillation signal;
A first band-pass filter that passes only the frequency component of the frequency-divided first local oscillation signal, an output signal from the first mixer, and the 1 / N frequency-divided output from the first band-pass filter A second mixer that mixes and outputs the first local oscillation signal, and a first IF that is a difference between the received signal group and the first local oscillation signal among signals output from the second mixer. An outdoor converter including a signal group and a second band-pass filter that passes the 1 / N-divided first local oscillation signal and outputs the signal as an outdoor converter output signal; A tuning amplifier for selecting, amplifying and outputting one IF signal group, a third mixer for mixing and outputting an output signal from the tuning amplifier and a second local oscillation signal, and an output from the third mixer Out of the signal An IF circuit that outputs a signal having a certain frequency as a second IF signal; a demodulation circuit that demodulates the second IF signal; and an IF circuit included in the outdoor converter output signal.
/ N frequency dividing the first local oscillation signal only
A band-pass filter, a crystal oscillator, a fourth mixer that mixes the 1 / N-divided first local oscillation signal output from the third band-pass filter with a signal from the crystal oscillator, A fourth band-pass filter that passes only a signal of a difference component between the 1 / N-divided first local oscillation signal and the signal of the crystal oscillator among the signals output from the mixers of FIG. A second 1 / N divider that divides the output signal by the same division ratio as the second 1 / N divider and outputs the divided signal, and a phase of the signal output from the fourth bandpass filter. A first phase comparator that compares the phase of the signal output from the first 1 / N divider and outputs the phase difference as a phase error signal, and a signal output from the first phase comparator. The phase error signal is converted to a DC voltage and output as VCO control. Low pass filter and said generating a signal of a frequency determined by a first voltage of the output VCO control signal from low-pass filter the first VC
A first VCO output as an O output signal and a second VC
A programmable divider that divides the O output signal by a dividing ratio set by a programmable divider setting signal and outputs the divided signal, and a signal of a frequency obtained by dividing a channel interval frequency in the received signal group by an integer to perform PLL control. A reference oscillator that outputs as a reference frequency reference signal, and compares the phase of the frequency reference signal output from the reference oscillator with the phase of the signal output from the programmable frequency divider,
A second phase comparator that outputs the phase difference as a phase error signal, and a second low-pass filter that converts the phase error signal output from the second phase comparator into a DC voltage and outputs the DC voltage as VCO control. A second VCO that generates a signal having a frequency determined by the voltage of the VCO control signal output from the second low-pass filter and outputs the signal as the second VCO output signal; and the first VCO output signal and the second VCO output signal. Fifth mixing and output of the second VCO output signal
And only the signal of the difference component between the first VCO output signal and the second VCO output signal among the signals output from the fifth mixer is passed as the second local oscillation signal. A fifth band-pass filter to be output, and a frequency obtained by subtracting the frequency of the 1 / N frequency-divided first local oscillation signal from the frequency of the crystal oscillator is multiplied by the frequency division ratio of the second 1 / N frequency divider. From the frequency, the center frequency of the second IF signal and the center frequency of the channel to be received in the first IF signal group are subtracted, and a value obtained by dividing the frequency obtained by the subtraction by the frequency of the frequency reference signal is a dividing ratio. And a control CPU for setting the programmable frequency divider with the programmable frequency divider by the programmable frequency divider setting signal. 8. The frequency of the 1 / N frequency-divided first local oscillation signal is higher than the frequency of the crystal oscillator, and the control CPU determines the frequency of the 1 / N frequency-divided first local oscillation signal from the frequency of the 1 / N frequency-divided first local oscillation signal. Subtracting the center frequency of the second IF signal and the center frequency of the channel to be received in the first IF signal group from a frequency obtained by multiplying the frequency obtained by subtracting the frequency of the second 1 / N frequency divider by: 8. The satellite receiver according to claim 7, wherein a value obtained by dividing the frequency obtained as a result of the subtraction by the frequency of the frequency reference signal is set as the frequency division ratio in the programmable frequency divider by the programmable frequency divider setting signal. 9. A parabolic antenna that receives a radio wave from a satellite and outputs the received signal group as a received signal group, an amplifier that amplifies and outputs a received signal group output from the parabolic antenna, and a signal having a certain frequency. 1
A first local oscillator that outputs a local oscillation signal; a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal; A first 1 / N frequency divider for dividing the frequency by a frequency division ratio and outputting it as a 1 / N frequency-divided first local oscillation signal;
A first band-pass filter that passes only the frequency component of the frequency-divided first local oscillation signal, an output signal from the first mixer, and the 1 / N frequency-divided output from the first band-pass filter A second mixer that mixes and outputs the first local oscillation signal, and a first IF that is a difference between the received signal group and the first local oscillation signal among signals output from the second mixer. An outdoor converter including a signal group and a second band-pass filter that passes the 1 / N-divided first local oscillation signal and outputs the signal as an outdoor converter output signal; A tuning amplifier for selecting, amplifying and outputting one IF signal group, a third mixer for mixing and outputting an output signal from the tuning amplifier and a second local oscillation signal, and an output from the third mixer Out of the signal An IF circuit that outputs a signal having a certain frequency as a second IF signal; a demodulation circuit that demodulates the second IF signal; and an IF circuit included in the outdoor converter output signal.
/ N frequency dividing the first local oscillation signal only
A band-pass filter, a crystal oscillator, a fourth mixer that mixes the 1 / N-divided first local oscillation signal output from the third band-pass filter with a signal from the crystal oscillator, A fourth band-pass filter that passes only a signal of a sum component of the 1 / N-divided first local oscillation signal and the signal of the crystal oscillator among the signals output from the mixers of FIG. A second 1 / N divider that divides the output signal by the same division ratio as the second 1 / N divider and outputs the divided signal, and a phase of the signal output from the fourth bandpass filter. A first phase comparator that compares the phase of the signal output from the first 1 / N divider and outputs the phase difference as a phase error signal, and a signal output from the first phase comparator. The phase error signal is converted to a DC voltage and output as VCO control. Low pass filter and said generating a signal of a frequency determined by a first voltage of the output VCO control signal from low-pass filter the first VC
A first VCO output as an O output signal and a second VC
A programmable divider that divides the O output signal by a dividing ratio set by a programmable divider setting signal and outputs the divided signal, and a signal of a frequency obtained by dividing a channel interval frequency in the received signal group by an integer to perform PLL control. A reference oscillator that outputs as a reference frequency reference signal, and compares the phase of the frequency reference signal output from the reference oscillator with the phase of the signal output from the programmable frequency divider,
A second phase comparator that outputs the phase difference as a phase error signal, and a second low-pass filter that converts the phase error signal output from the second phase comparator into a DC voltage and outputs the DC voltage as VCO control. A second VCO that generates a signal having a frequency determined by the voltage of the VCO control signal output from the second low-pass filter and outputs the signal as the second VCO output signal; and the first VCO output signal and the second VCO output signal. Fifth mixing and output of the second VCO output signal
And only the signal of the difference component between the first VCO output signal and the second VCO output signal among the signals output from the fifth mixer is passed as the second local oscillation signal. A fifth band-pass filter to be output, and a frequency obtained by adding the frequency of the crystal oscillator and the frequency of the 1 / N frequency-divided first local oscillation signal are multiplied by the frequency division ratio of the second 1 / N frequency divider The center frequency of the second IF signal and the center frequency of the channel to be received in the first IF signal group are subtracted from the obtained frequency, and a value obtained by dividing the resulting frequency by the frequency of the frequency reference signal is divided. An indoor tuner comprising: a control CPU for setting the programmable frequency divider as the ratio in the programmable frequency divider by the programmable frequency divider setting signal; 10. The indoor tuner, wherein the 1/3 output from the third band-pass filter is
A detection circuit for detecting the presence or absence of the N-divided first local oscillation signal, and outputting the detection result as a detection signal; and detecting a frequency of the crystal oscillator signal and a frequency of the 1 / N-divided first local oscillation signal. A second crystal oscillator that outputs a signal having a difference frequency; and a second crystal oscillator that is provided between the fourth band-pass filter and the first phase comparator.
A first selection circuit that selects one of the crystal oscillator and the signal from the fourth band-pass filter and outputs the selected signal to the first phase comparator; And a frequency divider provided between the reference oscillator and the second phase comparator, wherein the reference frequency signal and the signal from the frequency divider are provided according to an instruction of the selection control signal. And select either
And a second selection circuit that outputs to the control CPU the information as to whether the center frequency of the second IF signal is higher or lower than a set frequency as an AFC signal. The control CPU controls the first selection circuit by the selection control signal when the detection signal indicates that the 1 / N-divided first local oscillation signal is present. , The fourth
And outputs the signal from the band pass filter to the first phase comparator. The second control circuit controls the second selection circuit by the selection control signal to select the reference frequency signal. When the detection signal indicates that there is no 1 / N-divided first local oscillation signal, the first selection circuit is controlled by the selection control signal. Selecting an output signal from the second crystal oscillator, outputting the selected signal to the first phase comparator, controlling the second selection circuit by the selection control signal, and outputting the signal from the frequency divider. 10. The satellite receiver according to claim 8, wherein a signal is selected and output to the second phase comparator, and an AFC operation using the AFC signal is performed. 11. The outdoor converter further includes a band removal filter between the first mixer and the second mixer 7 for removing a frequency band of the 1 / N-divided first local oscillation signal. The satellite receiver according to any one of claims 1 to 10, further comprising: 12. A parabolic antenna that receives a radio wave from a satellite and outputs the received signal group as a received signal group, an amplifier that amplifies and outputs a received signal group output from the parabolic antenna, and a signal having a certain frequency. 1
A first local oscillator that outputs a local oscillation signal; a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal; A first 1 / N frequency divider for dividing the frequency by a frequency division ratio and outputting it as a 1 / N frequency-divided first local oscillation signal;
A first band-pass filter that passes only the frequency component of the frequency-divided first local oscillation signal, an output signal from the first mixer, and the 1 / N frequency-divided output from the first band-pass filter A second mixer that mixes and outputs the first local oscillation signal, and a first IF that is a difference between the received signal group and the first local oscillation signal among signals output from the second mixer. An outdoor converter including a signal group and a second band-pass filter that passes the 1 / N-divided first local oscillation signal and outputs the signal as an outdoor converter output signal; A tunable amplifier for selecting, amplifying and outputting one IF signal group, a third mixer for mixing and outputting an output signal from the tuned amplifier and a PLL frequency synthesizer output signal, An IF circuit that selects, amplifies and outputs a signal of a certain frequency among the output signals as a second IF signal;
A quadrature demodulation circuit for performing quadrature demodulation and A / D conversion on the second IF signal to output IQ data as digital data on a complex plane;
A demodulation circuit that corrects the phase and frequency of the Q data using the frequency indicated by the frequency setting signal as the center frequency and outputs the data as IQ demodulated data; A signal processing circuit for outputting a synchronization determination signal when the outdoor converter outputs the 1 / N signal.
A third band-pass filter that allows only the divided first local oscillation signal to pass therethrough, and a counter measurement value obtained by measuring the frequency of the 1 / N-divided first local oscillation signal output from the third band-pass filter. And a deviation from a set frequency of the 1 / N-divided first local oscillation signal as a frequency error from the counter measurement value, and demodulates a frequency setting signal that corrects the frequency error. An arithmetic circuit for outputting to the circuit, a PLL frequency synthesizer for outputting a signal of a set frequency as the PLL frequency synthesizer signal, a control CPU for controlling an output frequency of the PLL frequency synthesizer, and a PLL for the control CPU. An indoor tuner comprising a tuning instruction unit for giving an instruction for controlling the frequency synthesizer; and Satellite receiver composed. 13. A parabolic antenna that receives a radio wave from a satellite and outputs the received signal group as a received signal group, an amplifier that amplifies and outputs the received signal group output from the parabolic antenna, and a signal having a certain frequency. 1
A first local oscillator that outputs a local oscillation signal; a first mixer that mixes and outputs the signal output from the amplifier and the first local oscillation signal; A first 1 / N frequency divider for dividing the frequency by a frequency division ratio and outputting it as a 1 / N frequency-divided first local oscillation signal;
A first band-pass filter that passes only the frequency component of the frequency-divided first local oscillation signal, an output signal from the first mixer, and the 1 / N frequency-divided output from the first band-pass filter A second mixer that mixes and outputs the first local oscillation signal, and a first IF that is a difference between the received signal group and the first local oscillation signal among signals output from the second mixer. An outdoor converter including a signal group and a second band-pass filter that passes the 1 / N-divided first local oscillation signal and outputs the signal as an outdoor converter output signal; A tuned amplifier that selects, amplifies and outputs one IF signal group, a third mixer that mixes and outputs an output signal from the tuned amplifier and a PLL frequency synthesizer output signal, and a An IF circuit that selects, amplifies and outputs a signal of a certain frequency among the output signals as a second IF signal;
A quadrature demodulation circuit for shifting the center frequency when demodulating by the frequency error indicated by the frequency error signal, quadrature demodulating and A / D converting the second IF signal, and outputting IQ data as digital data on a complex plane; The phase and frequency of the IQ data output from the quadrature demodulation circuit are corrected using a predetermined frequency as a center frequency, and
A demodulation circuit that outputs Q demodulated data, a signal processing circuit that performs signal processing on the IQ demodulated data, outputs the demodulated data, and outputs a synchronization determination signal when synchronization is lost, and the outdoor converter output signal A third bandpass filter that allows only the 1 / N-divided first local oscillation signal to pass therethrough, and measures the frequency of the 1 / N-divided first local oscillation signal output from the third bandpass filter. A counter circuit for outputting the measured value as a counter measurement value;
An arithmetic circuit that detects a deviation of the local oscillation signal from a set frequency as a frequency error, and outputs the frequency error to the quadrature demodulation circuit as a frequency error signal; and a signal of a set frequency as the PLL frequency synthesizer signal. A PLL frequency synthesizer for outputting, a control CPU for controlling an output frequency of the PLL frequency synthesizer,
An indoor tuner comprising: a tuning instruction unit for instructing the control CPU to control the PLL frequency synthesizer; and a satellite receiver comprising: 14. The satellite receiver according to claim 12, wherein the 1 / N-divided first local oscillation signal is arranged in an upper frequency band of the first IF signal group. 15. The satellite receiver according to claim 12, wherein said 1 / N-divided first local oscillation signal is arranged in a lower frequency band of said first IF signal group. 16. The satellite receiver according to claim 12, wherein said arithmetic circuit is a CPU. 17. The satellite receiver according to claim 12, wherein said arithmetic circuit includes a plurality of logic circuits.