JP2001189670A - Received frequency converting device, frequency band switching method and receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a received frequency converting device and a frequency band switching method, with which accuracy in switching parallel connected band pass filters can be freely selected by changing the number of bits and positions of frequency setting data to be read and an image frequency band cab be attenuated for a fixed quantity in the frequency band of the band pass filters of the number of parallel connected band pass filters. SOLUTION: This device is provided with band pass filters 3 and 4 parallel connected to the output side of a low noise amplifier 1, mixer 6 for outputting an intermediate frequency signal by mixing an output signal from one of band pass filters 3 and 4 and a local oscillation signal, changeover switch 2 for switching the input of the band pass filters 3 and 4, changeover switch 5 for switching the output of the band pass filters 3 and 4, and control circuit for reading one part of the frequency setting data of a PLL circuit and controlling the switching operation of the changeover switches 2 and 5 corresponding to the read value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reception frequency conversion device and a frequency band switching method, and more particularly to a reception frequency conversion device suitable for automatically switching a plurality of band-pass filters connected in parallel in front of a mixer. The present invention relates to a device and a frequency band switching method, and a receiving device thereof.

[0002]

2. Description of the Related Art Conventionally, as a receiving frequency converter of a mixer used in a high-frequency stage of a receiving apparatus, there is one shown in FIGS. 4 and 5, for example. The receiving frequency converter shown in FIG. 4 is a low noise amplifier (LNA) for amplifying a high frequency (RF) signal.
ise Amp) 41, a band-pass filter (BPF) 42 that passes a frequency component of a predetermined band in the output signal of the low-noise amplifier 41, an output signal of the band-pass filter 42, and a local oscillation signal (Lo) from the oscillator. And a mixer (MIX) 43 for generating an intermediate frequency (IF) signal.

[0005] The receiving frequency converter shown in FIG. 5 includes a low noise amplifier 51 for amplifying a high frequency signal and a low noise amplifier 51.
Switch (RF SW1) 52 for switching the output of the device
And a band-pass filter (BPF1) 5 that passes a frequency component of a predetermined band in the output signal of the low noise amplifier 51.
3. A band-pass filter (BPF2) 54 and a changeover switch (RF S
W2) 55, and a mixer (MIX) 56 that mixes one output signal of both filters 53 and 54 and a local oscillation signal (Lo) from an oscillator to generate an intermediate frequency signal. In this case, the changeover switches 52 and 55 are manually operated switches.

As shown in FIGS. 4 and 5, in a conventional receiving frequency converter, in order to improve NF (noise figure) deterioration of the mixer due to thermal noise in an image frequency band, a band pass is provided before the mixer. A filter is connected to attenuate thermal noise in the image frequency band to improve the amount of NF degradation.

Here, as a conventional example relating to the prevention of bit error rate deterioration, see, for example, JP-A-11-205170.
Japanese Patent Application Laid-Open Publication No. H10-202,279 has been proposed. This publication aims to prevent the bit error rate from deteriorating due to undesired waves and high-frequency noise, and to input a high frequency signal of a received digital satellite broadcast signal of a plurality of channels and to receive a signal having the same frequency as the center frequency of a desired channel. High-frequency direct quadrature detection means for detecting a demodulated I signal by detecting a local oscillation signal and detecting a demodulated I signal by a signal obtained by shifting the local oscillation signal by 90 degrees to generate a Q signal, and a pass bandwidth corresponding to the desired channel. And a low-pass filter having a variable pass bandwidth configured to remove demodulated I and Q signals of a channel adjacent to the desired channel, as in the direct detection method, and a filter of the desired channel from the low-pass filter. A binary encoding means for encoding the demodulated I and Q into a binary number; a signal encoded by the binary encoding means being digitally demodulated and error-corrected; A digital demodulation means for outputting a digital demodulated signal of the channel, wherein the low-pass filter is set by switching a predetermined pass bandwidth. .

As a conventional example relating to noise reduction in a reception band, for example, one disclosed in Japanese Patent Application Laid-Open No. 11-242759 has been proposed. The publication is intended to reduce noise in a reception band and to reduce the influence of an unnecessary arriving wave serving as an interfering wave, and an intermediate frequency conversion means for converting a received signal into an intermediate frequency signal according to a reception frequency. A plurality of intermediate frequency filters each having a different set frequency for selecting an intermediate frequency signal, a changeover switch for switching these intermediate frequency filters and connecting to the intermediate frequency conversion means, and sequentially controlling the changeover switches in a constant cycle; ,
A switching timing generator that outputs an intermediate frequency filter state signal indicating a connection state of the intermediate frequency filter, and detects reception data output from the intermediate frequency filter;
Control means for outputting a changeover switch fixing command signal to the changeover timing generator so that the intermediate frequency filter outputting the reception data is continuously selected according to the intermediate frequency filter state signal. Is disclosed.

[0007]

However, the above-described prior art has the following problems.

As shown in FIGS. 4 and 5, in the conventional receiving frequency converter, a band-pass filter is connected in front of the mixer in order to improve the NF deterioration of the mixer due to thermal noise in the image frequency band. In addition, the thermal noise in the image frequency band is attenuated to improve the NF degradation amount. However, some reception frequency converters have a wide reception band (RF_BAND) with respect to the intermediate frequency (IF), so that a single band-pass filter cannot be used. For this reason, conventionally, the type of the receiving frequency converter is divided as shown in FIG. 4 to change the mounted band-pass filter, or the band-pass filter arranged in parallel as shown in FIG. Was manually switched.

An object of the present invention is to make it possible to freely select the switching accuracy of the band-pass filters connected in parallel by changing the number of bits and the position of the frequency setting data to be read, and to change the switching accuracy of the band-pass filters connected in parallel. An object of the present invention is to provide a receiving frequency conversion device and a frequency band switching method capable of attenuating a certain amount of image frequency band in a frequency band of a number × bandpass filter.

[0010]

According to the present invention, there is provided a receiving frequency converter for outputting an intermediate frequency signal based on an input high frequency signal, comprising: amplifying means for amplifying the high frequency signal; and a predetermined band for an output of the amplifying means. A plurality of band-pass means connected in parallel to pass the frequency components of the above, a mixing means for mixing an output signal of any of the band-pass means and a local oscillation signal and outputting an intermediate frequency signal, First switching means for connecting any input of the means to the amplifying means, second switching means for connecting any output of each of the band-pass means to the mixing means, and predetermined frequency setting data. Control means for controlling the switching operation of the first and second switching means by utilizing the control means.

Further, in the frequency band switching method applied to the receiving frequency conversion device, any one of a plurality of band-passing means connected in parallel for passing a frequency component of a predetermined band of the output of the amplifying means for amplifying the high-frequency signal. A first switching means for connecting an input to the amplifying means, and a mixing means for mixing an output signal of any of the band-passing means with a local oscillation signal and outputting an intermediate frequency signal; The switching operation of the second switching means for connecting the outputs is controlled based on the frequency setting data of the phase locked loop circuit.

The present invention also provides a receiver for outputting and demodulating an intermediate frequency signal based on an inputted high frequency signal, wherein the amplifying means amplifies the high frequency signal, and a frequency component of a predetermined band of the output of the amplifying means. A plurality of band-pass means connected in parallel to pass through, a mixing means for mixing an output signal of any of the band-pass means and a local oscillation signal and outputting an intermediate frequency signal, and any of the band-pass means First switching means for connecting the input to the amplification means,
Second switching means for connecting any of the outputs of the band-passing means to the mixing means, and control means for controlling the switching operation of the first and second switching means using predetermined frequency setting data. Wherein a demodulated signal is obtained by an intermediate frequency stage that amplifies and demodulates the intermediate frequency output of the mixing means.

The receiving frequency conversion apparatus according to the present invention will be described with reference to FIG. 1. Amplifying means (1) for amplifying the high-frequency signal, and passing a frequency component of a predetermined band of an output of the amplifying means. A plurality of band-passing means (3, 4) connected in parallel, a mixing means (6) for mixing an output signal of any of the band-passing means and a local oscillation signal and outputting an intermediate frequency signal, First switching means (2) for connecting any input of each band-pass means to the amplifying means, and second switching means (5) for connecting any output of each band-pass means to the mixing means. ) And control means (7) for controlling the switching operation of the first and second switching means using predetermined frequency setting data.

[Operation] The receiving frequency conversion apparatus of the present invention
The control means controls the switching operation of the first switching means and the second switching means based on the frequency setting data. For this reason, the switching accuracy of the plurality of band-pass units connected in parallel can be freely selected by changing the number of bits of the frequency setting data expressed by the predetermined number of bits read by the control unit and the reading position in the predetermined bits. In addition to this, it is possible to attenuate a certain amount of image frequency band by the number of band-pass units connected in parallel × the frequency band of the band-pass unit.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] Next, a first embodiment of the present invention will be described in detail with reference to the drawings.

(1) Description of Configuration FIG. 1 is a block diagram showing a configuration example of a reception frequency converter according to a first embodiment of the present invention. In FIG. 1, a receiving frequency converter according to an embodiment of the present invention includes a low noise amplifier (LN).
A) 1, a changeover switch (RF SW1) 2, a bandpass filter (BPF1) 3, and a bandpass filter (BP
F2) 4, a changeover switch (RF SW2) 5, a mixer (MIX) 6, a control circuit 7, and a PLL IC (Phase
Locked Loop IC) 8 and low-pass filter (LP)
F) 9 and a voltage controlled oscillator (VCO)
Oscillator) 10.

The above configuration will be described in detail.
Means HEMT (High Electron mobility Transistor)
Using circuits such as devices, SiGe devices, and MOSFETs,
Amplify high frequency (RF) signals. The changeover switch 2 is M
Control circuit 7 using OSFET, PIN diode, etc.
When the switch is switched to the contact 2a side, the output of the low-noise amplifier 1 is switched to the band-pass filter 3, and when the switch is switched to the contact 2b, the output of the low-noise amplifier 1 is switched to the band-pass filter 4. When the changeover switch 2 is switched to the contact 2a side using a CR filter, an LC filter, or the like, the bandpass filter 3 allows a frequency component of a predetermined band in the output signal of the low noise amplifier 1 to pass. When the changeover switch 2 is switched to the contact 2b side using a CR filter, an LC filter, or the like having a pass band different from that of the band-pass filter 3, the band-pass filter 4 outputs a predetermined signal from the low-noise amplifier 1. Passes frequency components of the band.

The changeover switch 5 connects the output of the band-pass filter 3 to the mixer 6 when the switch is switched to the contact 5a side under the control of the control circuit 7, and the band-pass filter when the switch is switched to the contact 5b. 4 is connected to the mixer 6. The mixer 6 mixes the output signal of the bandpass filter 3 or the bandpass filter 4 with the output signal of the voltage controlled oscillator 10 to generate an intermediate frequency (IF) signal. In this case, the low-noise amplifier 1 and the mixer 6 constitute a front-end part of the reception frequency converter.

The control circuit 7 controls the PL in the reception frequency converter.
A part of the L circuit frequency setting data is read, and the changeover switch 2 and the changeover switch 5 are controlled according to the read value. The control circuit 7 controls the bandpass filter 3,
The bandpass filter 4 is automatically switched. The PLL IC 8, the low-pass filter 9, and the voltage-controlled oscillator 10 constitute a known swallow counter PLL circuit. The swallow counter PLL circuit performs control so that the two phases match while comparing the phase of the output signal of the voltage controlled oscillator 10 with the phase of the frequency setting data.

The PLL IC 8 outputs to the low-pass filter 9 an error signal proportional to the phase difference between the output signal of the voltage controlled oscillator 10 and the frequency setting data. The low-pass filter 9 removes high-frequency components from the error signal and passes frequency components equal to or lower than a predetermined frequency. Voltage controlled oscillator 1
0 controls the oscillation frequency based on the output of the low-pass filter 9 and outputs a local oscillation signal to the PLL IC 8 and the mixer 6.

That is, the reception frequency converter according to the embodiment of the present invention includes a front end portion of the reception frequency converter including the low noise amplifier 1 and the mixer 6, the PLL IC 8, the low pass filter 9, the voltage control The control circuit 7 controls the swallow counter PLL circuit configured by the oscillator 10 to detect data of an arbitrary number of bits of the frequency setting signal and perform switching control of a frequency band according to the value of the detected data. In addition, it is configured by adding changeover switches 2 and 5 for switching frequency bands in response to the signals and bandpass filters 3 and 4.

FIG. 2 is a block diagram showing a configuration example of the control circuit 7 of the reception frequency converter according to the embodiment of the present invention. Control circuit 7 for receiving frequency converter according to the embodiment of the present invention
Is a mask circuit 21 and a serial / parallel conversion circuit 2
2 is provided.

The above configuration will be described in detail.
Extracts predetermined data of an arbitrary number of bits of a B counter setting signal that roughly counts from the input frequency setting data and an A counter setting signal that subdivides the B counter. In this case, the number of switches can be arbitrarily set according to the number of bits extracted by the mask circuit 21. Cereal/
The parallel conversion circuit 22 receives an arbitrary bit extracted by the mask circuit 21, converts the serial data into parallel data, and inputs the data to the changeover switches 2 and 5. Therefore, the switching of the bandpass filters 3 and 4 follows the setting signal of the B counter, and the master circuit does not need to read the setting signal of the A counter.

(2) Description of Operation Next, the operation of the embodiment of the present invention will be described in detail with reference to FIGS.

The control circuit 7 of the reception frequency converter extracts data of an arbitrary number of bits of the B counter setting signal by the mask circuit 21 from the input frequency setting data of the predetermined number of bits. The number of switching can be set arbitrarily by the number of bits to be taken out. Next, an arbitrary bit extracted by the mask circuit 21 of the control circuit 7 is input to the serial / parallel conversion circuit 22 of the control circuit 7, converted from serial data to parallel data, and input to the changeover switches 2 and 5. You. The changeover switches 2 and 5 are provided with a band-pass filter 3 and a band-pass filter 4 in accordance with a signal input from the serial / parallel conversion circuit 22 of the control circuit 7.
, The frequency band is automatically switched.

Here, a supplementary description of this embodiment will be given.
Taking a pulse swallow PLL circuit as an example, the oscillation frequency (Frf) can be obtained by the following equations (Equations 1 and 2).
Normally, the comparison frequency and the division ratio of the two modulus prescaler are fixed, so that the approximate oscillation frequency (Frf) can be known by reading the value of the B counter.

Frf = N × comparison frequency (Equation 1) N = (B × Y + A) (Equation 2) N: division ratio, Y: 2 modulus prescaler division number A: A counter value, B: B counter value or more As described above, according to the embodiment of the present invention, the bandpass filter shown in FIG.
The switching of the frequency band, which was handled by the manual switching shown in FIG. 5 of the above-described conventional example, is replaced by a control circuit 7 in which a part of the PLL circuit frequency setting data in the receiving frequency converter is converted as shown in FIG. The reading and controlling the changeover switches 2 and 5 in accordance with the value, the bandpass filters 3 and 4 are automatically switched. By connecting the bandpass filters 3 and 4 in multiple stages in parallel, the low noise amplifier 1 or the mixer 6
And the switching accuracy of the bandpass filters 3 and 4 can be arbitrarily set according to the number of bits and the position of the frequency setting data read by the control circuit 7.

Therefore, the switching accuracy of the band-pass filters connected in parallel can be freely selected by changing the number of bits of the frequency setting data having a predetermined number of bits read by the control circuit 7 and the reading position of the predetermined number of bits. And the number of bandpass filters connected in parallel ×
An effect is obtained that a certain amount of image frequency band can be attenuated in the frequency band of the band-pass filter.

[Second Embodiment] Next, a second embodiment of the present invention will be described in detail with reference to the drawings.

(1) Description of Configuration FIG. 3 is a block diagram showing a configuration example of a reception frequency converter according to a second embodiment of the present invention. In FIG. 3, a receiving frequency converter according to another embodiment of the present invention includes a changeover switch (R
F SW1) 31 and low noise amplifier (LNA1) 32
, A low noise amplifier (LNA2) 33, a bandpass filter (BPF1) 34, and a bandpass filter (BPF2)
35, a changeover switch (RF SW2) 36, a mixer (MIX) 37, and a control circuit 38.

The above configuration will be described in detail.
Converts the radio-frequency (RF) signal to the low-noise amplifier 32 when switched to the contact 31a side under the control of the control circuit 38.
When the switch is switched to the contact 31b side, a high frequency (RF) signal is supplied to the low noise amplifier 33. The low noise amplifiers 32 and 33 amplify high frequency (RF) signals. The band-pass filter 34 is configured such that the changeover switch 31
When it is switched to the side, the frequency component of a predetermined band in the output signal of the low noise amplifier 32 is passed. When the changeover switch 31 is switched to the contact 31b side, the bandpass filter 35 passes a frequency component of a predetermined band in the output signal of the low noise amplifier 33.

The switch 36 connects the output of the band-pass filter 34 to the mixer 37 when the switch 36 is switched to the contact 36a side under the control of the control circuit 38.
When it is switched to the side, the output of the band-pass filter 35 is connected to the mixer 37. The mixer 37 mixes an output signal of the band-pass filter 34 or the band-pass filter 35 with an output signal of a voltage-controlled oscillator (not shown) to generate an intermediate frequency (IF) signal.

The control circuit 38 controls P in the reception frequency converter.
A part of the LL circuit frequency setting data is read, and the changeover switch 31 and the changeover switch 36 are selected according to the read value.
Control. Thereby, the band-pass filter 34 and the band-pass filter 35 are automatically switched. The internal configuration of the control circuit 38 is the same as that of the above-described embodiment shown in FIG.
Since it is the same as that of FIG.

(2) Description of Operation Next, the operation of the second embodiment of the present invention will be described in detail with reference to FIG. The control circuit 38 of the reception frequency converter extracts data of an arbitrary number of bits from the input frequency setting data, converts the serial data into parallel data, and
1 and 36 are input. The changeover switches 31 and 36 are connected to the band-pass filter 3 according to the signal input from the control circuit 38.
4 and the band-pass filter 35,
Performs automatic frequency band switching. That is, by switching the frequency band of the band-pass filters 34 and 35 including the low-noise amplifiers 32 and 33, the frequency band of the band-pass filters 34 and 35 can be extended to the use frequency range of the mixer 37.

As described above, according to the second embodiment of the present invention, the switching accuracy of the band-pass filters connected in parallel is determined by the bit of the frequency setting data read by the control circuit 38, as in the above embodiment. By changing the number and position, it is possible to select freely, and it is possible to attenuate a certain amount of image frequency band by the number of band-pass filters connected in parallel x the frequency band of the band-pass filter. Can be

Here, the set frequency of the PLL is obtained by the above (Equation 1) and (Equation 2). For example, the fact that the switching accuracy can be set at the BIT position of the frequency setting data means that when the setting frequency step (comparison frequency in (Equation 1)) is 250 kHz, the lowest BIT of the A counter
Is taken out and BAND switching is performed.
AND switching can be performed, the lower 2 bits of the A counter are taken out, and BAND switching is performed.
Can be switched. Switching the switching accuracy based on the number of bits to be read means that reading from the lowest BIT of the A counter to 3 BITs allows 8 steps of switching, and reading up to the 4th bit enables 16 steps of switching. It is possible.

In addition, in addition to the high-frequency stage used in each of the above-described embodiments, in the receiving device, the transmitted signal is demodulated to a baseband by the intermediate frequency stage, and the baseband signal is transmitted in a predetermined format. Data, voice,
By outputting the image signal, it is possible to output as accurate data with less intermodulation and intermodulation.

[0038]

As described above, according to the present invention, the control means of the receiving frequency converter reads a part of the frequency setting data of the phase locked loop circuit, and the first switching means according to the read value. And controlling the switching operation of the second switching means to control the switching of the plurality of band-pass means connected in parallel, the switching accuracy of the plurality of band-pass means connected in parallel, the frequency setting read by the control means By changing the number of bits and the position of the data, it is possible to freely select the data, and it is possible to attenuate a certain amount of the image frequency band by the number of band-pass means connected in parallel times the frequency band of the band-pass means. Is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a reception frequency converter according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a control circuit of the reception frequency converter according to the embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration example of a reception frequency converter according to the embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration example of a conventional reception frequency converter.

FIG. 5 is a block diagram illustrating a configuration example of a conventional reception frequency converter.

[Explanation of symbols]

 1, 32, 33 Low-noise amplifier 2, 5, 31, 36 Switch 3, 4, 34, 35 Band-pass filter 6, 37 Mixer 7, 38 Control circuit 8 PLL IC 9 Low-pass filter 10 Voltage-controlled oscillator

Claims (7)

[Claims] 1. A receiving frequency converter for outputting an intermediate frequency signal based on an input high frequency signal, comprising: an amplifying means for amplifying the high frequency signal; and a parallel connection for passing a frequency component of a predetermined band of an output of the amplifying means. A plurality of band-pass units, a mixing unit that mixes an output signal of any of the band-pass units with a local oscillation signal and outputs an intermediate frequency signal, and an input of any of the band-pass units. First switching means connected to the amplifying means, second switching means connecting any output of each of the band-pass means to the mixing means, and the first and second using predetermined frequency setting data Control means for controlling the switching operation of the second switching means. 2. A receiving frequency conversion device for outputting an intermediate frequency signal based on an input high frequency signal, comprising: a plurality of amplifying means connected in parallel for amplifying the high frequency signal; A plurality of band-pass means for passing a frequency component of a predetermined band of the output of the amplifying means, a mixing means for mixing any output signal of each of the band-pass means and a local oscillation signal and outputting an intermediate frequency signal, First switching means for connecting any input of each amplifying means to the supply unit of the high-frequency signal, second switching means for connecting any output of each of the band-pass means to the mixing means, Control means for controlling the switching operation of said first and second switching means using said frequency setting data. 3. The control means reads a part of the frequency setting data of the phase locked loop circuit as the predetermined frequency setting data, and performs a switching operation of the first and second switching means according to the read value. The receiving frequency conversion device according to claim 1, wherein the receiving frequency conversion device performs control. 4. The extracting device according to claim 1, wherein the control unit extracts serial data of an arbitrary number of bits from frequency setting data of the phase locked loop circuit, and converts the serial data of the arbitrary number of bits extracted by the extracting unit into parallel data. The receiving frequency conversion device according to claim 3, further comprising a conversion unit that converts and outputs the converted signal to the first and second switching units. 5. A frequency band switching method applied to a reception frequency conversion device, wherein: any one of a plurality of band-passing means connected in parallel for passing a frequency component of a predetermined band of an output of an amplifying means for amplifying a high-frequency signal. A first switching means for connecting an input to the amplifying means, and a mixing means for mixing an output signal of any of the band-passing means with a local oscillation signal and outputting an intermediate frequency signal; A switching operation of a second switching means for connecting the outputs, based on frequency setting data of a phase-locked loop circuit. 6. A frequency band switching method applied to a receiving frequency conversion device, wherein a frequency component of a predetermined band of an output of each of the amplifying means is connected to a plurality of amplifying means connected in parallel for amplifying a high frequency signal. First switching means for connecting any input of a plurality of band-pass means to the supply section of the high-frequency signal, and mixing an output signal of any of the band-pass means with a local oscillation signal to produce an intermediate frequency signal Frequency band switching, wherein the switching operation of the second switching means for connecting any one of the outputs of the respective band-passing means to the mixing means for outputting a signal is controlled based on frequency setting data of a phase-locked loop circuit. Method. 7. A receiving apparatus for outputting and demodulating an intermediate frequency signal based on an input high-frequency signal, comprising: amplifying means for amplifying the high-frequency signal; A plurality of connected band-pass units, a mixing unit that mixes an output signal of any of the band-pass units with a local oscillation signal and outputs an intermediate frequency signal, and an input of any of the band-pass units. The first switching means connected to the amplifying means, the second switching means connecting any output of each of the band pass means to the mixing means, and the first and the second using predetermined frequency setting data Control means for controlling a switching operation of a second switching means, wherein a demodulated signal is obtained by an intermediate frequency stage for amplifying and demodulating an intermediate frequency output of the mixing means.