JP3260085B2 - Receiver with antenna booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver with an antenna booster, and particularly to DAB band II and band II.
The present invention relates to a receiver with an antenna booster suitable for receiving a broadcast having a wide reception frequency band such as I and band L.

[0002]

2. Description of the Related Art In Europe, DAB (Digital Audio Broadcastin) for performing radio broadcasting with digital audio signals is used.
Commercialization of g) is in progress. This DAB is a newly developed OFDM (Orthogonal Frequency) that is less susceptible to the effects of multipath generated in FM broadcasting.
Division multiplex (orthogonal frequency division multiplex) modulation method is adopted. In OFDM, broadcast data for a plurality of programs is converted from serial to parallel, and then inverse FFT (Fast Fourier tra
nsform), and multiplexes on a number of orthogonal carriers. Then, each carrier is DQPSK-modulated, and then transmitted collectively (a group of carriers transmitted collectively is called an ensemble, and the occupied frequency bandwidth is 1.5 MHz). The receiving side has a 1.5 MHz occupied frequency bandwidth of 1
The group of carriers for the ensemble is collectively received and DQPS
After demodulating the received data group by performing K demodulation, the broadcast data is further demodulated by performing FFT conversion, parallel / serial conversion, deinterleaving on the time axis and frequency axis, and error detection / correction. Then, the audio data of the desired program (MPEG1 layer I
I) is extracted and decompressed, and after D / A conversion, audio is output.

[0003] There are three reception frequency bands in DAB, and the conventional FM radio broadcast band (87.5 to 108 MH).
z), band II, TV broadcast band (175-250)
MHz) using band III, 1.452 to 1.49.
The band L is 2 GHz. When a mobile body receives the above three bands of DAB radio waves, the antenna received signal is subjected to RF amplification, conversion to an intermediate frequency signal, and D for each carrier.
A tuner for performing QPSK demodulation requires a high-performance one having sensitivity characteristics and a high noise figure, and the configuration is complicated and expensive. However, the use of an antenna booster circuit can reduce the performance load of the tuner. . For example, a configuration as shown in FIG. 5 is conceivable for an antenna booster circuit usable in DAB. 1 is an antenna element, and a band I
I, band III, and band L share. Reference numeral 10 denotes an antenna booster circuit, which amplifies an antenna reception signal at the installation location of the antenna element 1 to improve the noise figure of the receiving system, and also places the sensitivity characteristic of the tuner of the receiver body 30 and the performance load of the noise figure. To reduce Of which, 11
Is the reception frequency band of band L (1.452 to 1.492)
GHz) as a pass band.
F) and 12 are low-noise amplifiers (LNA) for amplifying the antenna reception signal passed through the band-pass filter 11, and 13 is a reception frequency band (87.5-250 MHz) combining the reception frequency bands of bands II and III. A band-pass filter (BPF) having a pass band, 14 is a band-pass
A low-noise amplifier (LNA) for amplifying the antenna reception signal passing through 3, a combiner (combiner) 15 for combining the outputs of the low-noise amplifiers 12 and 14, and 50 for the output of the combiner 15 Is a coaxial cable that transmits to the
The DC power supply voltage + V is superimposed on the center conductor side of the coaxial cable 50 on the side of the receiver main body 30. Reference numerals 16 and 31 denote DC cut capacitors, and reference numeral 17 denotes + V superimposed on the coaxial cable 50 on the receiver main body side.
LPF that feeds powers 2 and 14. Reference numeral 41 denotes an LPF for cutting the antenna reception signal component so as not to flow around the DC power supply + V. According to the antenna booster circuit 10 configured as described above, the received signal of the antenna can be amplified at the installation location of the antenna element 1, so that even if noise is picked up by the coaxial cable 50, the noise figure is not significantly deteriorated. In addition, the required performance of the sensitivity characteristic and noise figure for the tuner 32 can be moderated.

[0004]

However, in the above configuration example, since the reception frequency band (87.5 to 250 MHz) combining the reception frequency bands of bands II and III is wide, it is possible to receive the jamming radio waves such as TV. easy. Low noise amplifier 1
The larger the gain of No. 4 is, the smaller the noise figure of the entire receiving system can be made. However, if the gain is large, the low noise amplifier 14 easily saturates with the total input power of the interfering signal, and nonlinear distortion is generated and the receiving sensitivity is reduced. Will be worse. Therefore, the gain of the low-noise amplifier 14 cannot be increased, and the noise figure of the receiving system deteriorates, and the sensitivity characteristics and the required performance of the noise figure for the tuner 32 increase, resulting in a problem that the circuit configuration becomes complicated and expensive. is there. An object of the present invention is to provide a receiver with an antenna booster circuit that can improve the noise figure of a receiving system, reduce the sensitivity characteristic to a tuner, and reduce the required performance of the noise figure in view of the above-described problems of the related art. .

[0005]

According to a first aspect of the present invention, there is provided a receiver with an antenna booster, wherein the antenna booster circuit and the receiver main body are connected by a transmission cable. The side is connected to the antenna element, the occupied frequency bandwidth of the desired signal is used as the pass bandwidth, the center frequency is variable in the reception frequency band, the bandpass filter is input, the low noise amplifier that inputs the output of the bandpass filter, and the low noise Output side of amplifier
And a transmission circuit, and a control circuit for variably controlling the center frequency of the filter in conjunction with a change in the tuning frequency on the receiver body side. As a result, even if the receiving frequency band is wide and there are many interfering stations, the input of the low-noise amplifier can be narrowed down to only the occupied frequency bandwidth of the desired signal. Thus, the low-noise amplifier can be hardly saturated by the input of the interfering signal. Therefore, non-linear distortion hardly occurs, and the gain of the low-noise amplifier can be increased to reduce the noise figure of the receiving system. As a result, the sensitivity characteristics and noise figure performance conditions required for the tuner can be relaxed, and the configuration can be simplified and inexpensive. In addition, the impedance fluctuation of the receiving end of the receiver body
When there is a mismatch between the transmission cable and the receiving end at
Proceeding from the low-noise amplifier to the receiving end via the transmission cable
The signal received by the antenna is low again after being reflected at the receiving end.
The component that returns to the noise amplifier is the attenuation of the attenuator
VS on the transmission cable
WR (voltage standing wave ratio) deterioration can be prevented and transmission cable
Has a non-flat frequency-gain characteristic.
Wear.

[0006]

[0007]

[0008]

In a receiver with an antenna booster according to a second aspect of the present invention, in the receiver with the antenna booster in which the antenna booster circuit and the main body of the receiver are connected by a transmission cable, each of the antenna booster circuits has a different reception frequency band. The input side is connected to the antenna element, and at least one has the same pass bandwidth as the occupied frequency bandwidth of the desired signal, the center frequency is variable within the receive frequency band, and the other is the receive frequency band. A band-pass filter having a fixed pass band, a plurality of low-noise amplifiers individually provided on the output side of each band-pass filter, and a combination in which the output of each low-noise amplifier is input and the output side is connected to a transmission cable. While the receiver and the receiver body are receiving a reception frequency band corresponding to a certain band-pass filter having a variable center frequency, the receiver body and the receiver are connected to a change in the tuning frequency. To is characterized in that a control circuit for the variable control of the center frequency for the bandpass filter. Accordingly, when there are a plurality of reception frequency bands, for a reception frequency band in which the reception frequency band is wide and many interference signals are present, it is necessary to pass an input of a low noise amplifier corresponding to the reception frequency band to pass a desired signal. Since the bandwidth can be narrowed down to only the bandwidth, it is possible to prevent the interfering signal from being mixed into the low-noise amplifier, and the low-noise amplifier is less likely to be saturated by the input of the interfering signal. Therefore, non-linear distortion hardly occurs, and the gain of the low-noise amplifier can be increased to reduce the noise figure of the receiving system. As a result, the sensitivity characteristics and noise figure performance conditions required for the tuner can be relaxed, and the configuration can be simplified and inexpensive.

According to a third aspect of the present invention, there is provided a receiver with an antenna booster according to the second aspect .
Attenuator was provided between the output side of the
It is characterized. As a result, when a mismatch occurs between the transmission cable and the power receiving end due to impedance fluctuations at the power receiving end of the receiver main body, the antenna receiving signal transmitted from the combiner to the power receiving end via the transmission cable is received by the power receiving end. The component that returns to the combiner side after being reflected by the attenuator can be attenuated by the attenuation of the attenuator, so that the VSWR in the transmission cable can be prevented from deteriorating, and the transmission cable has a non-flat frequency-gain characteristic. Can be suppressed.

[0011]

[0012]

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a DAB receiving system for a vehicle, and the same components as those in FIG. 4 are denoted by the same reference numerals. Reference numeral 1 denotes an antenna element installed at a predetermined position of the vehicle,
In bands II, III, and L. Reference numeral 10A denotes an antenna booster circuit, which is installed at the same place as the antenna element 1 and improves the noise figure of the receiving system by amplifying the antenna reception signal, thereby increasing the sensitivity characteristics and noise figure of the tuner 32. Reduce the burden. Among the antenna booster circuits 10A, 11A has a pass band width of 1.5 MHz, which is an occupied frequency bandwidth for one ensemble of DAB, and a reception frequency band of band L (1.452 to 1.4).
In the range of 92 GHz), a band-pass filter (BPF) whose center frequency is variable by voltage control, 12 is a low-noise amplifier (LNA) that amplifies an antenna reception signal passed through the band-pass filter 11A, and 13A is one ensemble of DAB It has a pass bandwidth of 1.5 MHz, which is the occupied frequency bandwidth of 1 minute, and in the reception frequency band (87.5 to 250 MHz) combining the reception frequency bands of bands II and III, the center frequency is controlled by voltage control. A variable band-pass filter (BPF) 14 is a low-noise amplifier (LN) that amplifies an antenna reception signal passed through the band-pass filter 13A.
A) and 15 are combiners (combiners) that combine the outputs of the low-noise amplifiers 12 and 14, in which a diplexer, which is a type of duplexer, is used.

Reference numeral 50 denotes a coaxial cable serving as a transmission cable for transmitting the output of the synthesizer 15 to a receiver main body 30A installed at a predetermined location in the vehicle cabin, and a central conductor of the coaxial cable 50 at the receiver main body 30A side. DC power supply voltage + V '
Are superimposed. In the receiver main body 30A, a tracking control signal TR created by a controller described later is also superimposed on the center conductor of the coaxial cable 50. The tracking control signal TR is interlocked with the tuning frequency, and f ₁ to f out of the reception frequency band (here, 87.5 MHz or less).
is a sine wave whose frequency varies in a range of f _2. 18 is-
An attenuator (ATT) having an attenuation of 3 dB,
The VSWR (voltage standing wave ratio) of the coaxial cable 50 is prevented from deteriorating.

Reference numeral 17 denotes a DC power supply voltage (attenuated by -3 dB from + V ') superimposed on the coaxial cable 50 from the antenna receiving signal input side of the attenuator 18, and supplies the low noise amplifiers 12, 14 and the like. The value of + V ′ ≒ (+ V) × 1.41 is set so that the output of the LPF 17 has the same voltage value as the configuration example of FIG. 5 (for example, + V is +8. When it was 5V, + V '≒ 12V). Reference numeral 19 denotes a tracking control circuit, which extracts a tracking control signal TR superimposed on the coaxial cable 50 from the input side of the attenuator 18, converts the tracking control signal TR into a tracking control voltage v, and outputs the tracking control voltage v to the band-pass filters 11A and 13A. , The center frequency of the pass band of the band-pass filters 11A and 13A is varied. The tracking control circuit 19 has 87.
Much lower than 5 MHz, the tracking control signal TR
A band pass filter (BPF) for extracting a tracking control signal TR from the input side of the attenuator 18 and a tracking control signal TR, wherein a frequency range from f _{0 to} f ₃ including a minimum frequency f ₁ to a maximum frequency f ₂ of And a frequency / voltage converter (F / V) for generating the tracking control voltage v. 2
2 passes a frequency component higher than the frequency f _HC (f ₃ <f _HC <87.5 MHz) so that the DC power supply voltage component and the tracking control signal TR do not enter the combiner 15 from the attenuator 18 side. High-pass filter (H
PF).

In the receiver main unit 30A, the reference numeral 33 allows a frequency component higher than a frequency f _HC (f ₃ <f _HC <87.5 MHz) to pass therethrough, and directs a DC power supply voltage component (+ V) from the coaxial cable 50 side to the tuner 32 side. ′) And a high-pass filter (H
PF). The tuner 32 performs RF amplification, conversion to an intermediate frequency signal and amplification, and DQPSK demodulation for each carrier with respect to the antenna reception signal. Tuner 32 is band II
-III shared front end, PLL frequency synthesizer local oscillator, IF circuit, and band L dedicated front end, PLL frequency synthesizer local oscillator, I
It has an F circuit, and the DQPSK demodulation circuit is shared by all bands II, III, and L. Band switching control for the tuner 32 (switching between band II-III and band L) and tuning frequency variable control are performed by a controller. Numeral 34 denotes a signal processing circuit, which applies F.sub.
Broadcast data is demodulated by performing FT conversion, parallel-serial conversion, deinterleaving on the time axis and frequency axis, and error detection / correction. Then, the audio data (compressed data according to the MPEG1 layer II) of the user desired program selected by the controller is extracted, decompressed and output. 35 is a D / A converter for converting the expanded audio data into an analog audio signal;
36 is an amplifier for amplifying the audio signal, and 37 is a speaker.

Reference numeral 38 denotes an operation unit for performing band selection operations of bands II, III, and L, tuning frequency variable operation, and selection operation of a desired program in an ensemble, and 39 denotes a controller constituted by a microcomputer. According to the tuning frequency variable operation, the band II-I
Switching control to the II side or band L side and tuning frequency variable control are performed, and program selection control for the signal processing circuit 34 is performed according to a program selection operation. The controller 39
Generates a sine-wave tracking control signal TR whose frequency changes in conjunction with the tuning frequency when receiving the bands II-III and L, respectively. Specifically, as shown in FIG. 2, at the time of band II-III reception,
The controller 39 changes the frequency of the tracking control signal TR from f ₁ to f ₂ in proportion to the change of the tuning frequency F from 87.5 MHz to 250 MHz (f
_{1 <f 2 <f HC <} 87.5MHz). When the band L is received, the controller 39 sets the tuning frequency F to 1.4.
The frequency of the tracking control signal TR is changed from f ₁ to f ₂ in proportion to the change from 52 GHz to 1.492 GHz.
To change. The tracking control signal TR is f _{0 to} f
₃ (0 <f ₀ <f ₁ , f ₂ <f ₃ <f _HC ) is applied to the center conductor of the coaxial cable 50 via a band pass filter (BPF) 40 having a pass band.

On the side of the antenna booster circuit 10A, the frequency / voltage converter 21 of the tracking control circuit 19
When the frequency f of the tracking control signal TR changes from f ₁ to f _2, is changed in proportion to said change of the voltage of the tracking control voltage v from v ₁ to _{v 2 (v 1 <v 2} ). When the tracking control voltage v changes from v ₁ to v ₂ , the band-pass filter 11A changes in proportion to the change in v.
Center frequency of passband of 87.5MHz to 250M
Hz, and the center frequency of the pass band of the band-pass filter 13A changes from 1.452 GHz to 1.492 GHz. Reference numeral 41 denotes an LPF for cutting the antenna reception signal component so as not to flow around the DC power supply + V.

Next, the operation of the above embodiment will be briefly described with reference to FIG. FIG. 2 is a diagram showing the relationship between the tuning frequency, the frequency of the tracking control signal, and the voltage of the tracking control voltage. Note that f ₀ = 150 kHz,
f ₁ = 200 kHz, f ₂ = 300 kHz, f ₃ = 35
0 kHz, f _HC = 86 MHz, v ₁ = 2 V, v ₂ = 8 V
And Further, it is assumed that + V '= 12 V. Receiving band II-III (see FIG. 2) DC power supply voltage + V 'applied to the center conductor of coaxial cable 50 in receiver main body 30A is sent to antenna booster circuit 10A via coaxial cable 50. The LPF 17 of the antenna booster circuit 10A extracts the DC power supply voltage superimposed on the coaxial cable 50 from the input side of the attenuator 18 and outputs the DC power supply voltage to the low noise amplifiers 11A and 13A and the frequency / voltage converter 21 to be in an operating state. The user broadcasts at band II reception frequency F = 105 MHz D
When band II is selected on the operation unit 38 to listen to the AB program, the controller 39 controls the tuner 32 to switch to band II-III. Subsequently, when an operation of varying the tuning frequency F is performed on the operation unit 38, the controller 39 performs tuning frequency variable control on the tuner 32. At some point, the tuning frequency of tuner 32 is F _X = 1
When the frequency is 00 MHz, the controller 38 outputs F _x
To generate a tracking control signal TR of a corresponding frequency f _x = 207.7kHz, it is applied to the central conductor of the coaxial cable 50 through a band pass filter 40.

In the antenna booster circuit 10A, the band-pass filter 20 of the tracking control circuit 19 extracts the tracking control signal TR superimposed on the coaxial cable 50 from the input side of the attenuator 18. Then, the frequency / voltage converter 21 converts the tracking control voltage v _x = 2.46 V corresponding to the frequency f _x to the band-pass filter 13.
Output to A. As a result, the center frequency of the pass band of the band-pass filter 13A becomes 100 MHz, which is the same as the tuning frequency of the tuner 32, and only the band component of 99.25 MHz to 100.75 MHz of the received signal of the antenna element 1 is passed. If the operation by the user raise the tuning frequency from F _x, the controller 39 is a control for increasing the tuning frequency to the tuner 32, in conjunction with this increasing the frequency of the tracking control signal TR from f _x. Therefore, the frequency / voltage converter 2 of the tracking control circuit 19
Tracking control voltage output from 1 up from even v _x, the center frequency of the band-pass filter 13A is increased from F _x.

When the tuning operation is stopped when the tuning frequency F becomes 105 MHz, the controller 39 sets the frequency f of the tracking control signal TR to 210.8 kHz. Then, the frequency / voltage converter 21 obtains v = 2.65V
And the center frequency of the bandpass filter 13A is 10
5 MHz, which is 104.25 MHZ which is the occupied frequency band of the desired signal among the received signals of the antenna element 1.
Pass only the band component of z to 105.75 MHz. The low noise amplifier 14 amplifies the output of the band pass filter 13A. Here, even if there are many interfering stations in the bands II-III, the input of the low noise amplifier 14 is narrowed down to only the occupied frequency bandwidth of the desired signal. Can be avoided, and the low-noise amplifier 14 can hardly be saturated by the input of the interfering signal. Therefore, non-linear distortion hardly occurs, and the gain of the low-noise amplifier 14 can be increased to reduce the noise figure of the receiving system.

The output of the low noise amplifier 14 is
The signal is transmitted to the receiver main body 30A via the high-pass filter 22, the attenuator 18, and the coaxial cable 50, and is input to the tuner 32 via the high-pass filter 33. At this time, since the attenuator 18 is provided, when a mismatch occurs with the coaxial cable 50 due to impedance fluctuation at the input end of the tuner 32 which is the power receiving end of the receiver main body 30A, the output from the synthesizer 15 is output. And coaxial cable 5
With respect to the antenna received signal that has traveled to the receiver main body 30A side through 0, the reflected wave component reflected at the input end of the tuner 32 of the receiver main body 30A and then returned to the combiner 15 side via the coaxial cable 50 is- Since it can be attenuated by 3 dB, it is possible to prevent deterioration of the VSWR (voltage standing wave ratio) in the coaxial cable 50 and to suppress the coaxial cable 50 from having non-flat frequency-gain characteristics. Also,
In the antenna booster circuit 10A, since the diplexer is used for the combiner 15, the degree of separation between the input terminals is high, and the output of the low noise amplifier 12 does not enter the 14 and does not generate intermodulation distortion. In addition, due to the presence of the high-pass filter 22, the DC power supply voltage and the tracking control signal TR superimposed on the coaxial cable 50 are combined with the combiner 1
5, thereby suppressing the saturation of the output of the low noise amplifier 14 and the occurrence of intermodulation distortion. The high-pass filter 33 is also used in the receiver body 30A.
Prevents the DC power supply voltage + V 'and the tracking control signal TR from entering the tuner 32, thereby suppressing saturation of the RF circuit of the tuner 32 and occurrence of intermodulation distortion.

Tuner 32 to which antenna reception signal is input
Performs RF amplification, tuning to a desired signal, conversion to an intermediate frequency signal, DQPSK demodulation, and outputs a received data group for each carrier. This received data group is processed by the signal processing circuit 34 into F
Broadcast data is demodulated after performing FT conversion, parallel-serial conversion, deinterleaving on the time axis and frequency axis, and error detection / correction. When the user selects a desired program on the operation unit 38, the controller 39 controls the signal processing circuit 34 to
The compressed audio data of the program desired by the user is extracted, expanded, and output from the broadcast data. Decompressed audio data is D
The signal is converted into an analog audio signal by the / A converter 35, amplified by the amplifier 36, and then output from the speaker 37. This allows the user to listen to the desired program of band II. Thereafter, when it is desired to change to a program of a certain reception frequency in band III, the tuning frequency is variably operated by the operation unit 38, and as in the case of band II, the center frequency of the pass band of the band-pass filter 13A is changed. Since the frequency is changed to match the new tuning frequency, a desired program can be heard by selecting a program.

Reception of band L (see FIG. 2) When the user wants to listen to the DAB program broadcast at the reception frequency of 1.472 GHz of band L,
Select The controller 39 controls the tuner 32 to switch to the band L. Subsequently, when the tuning frequency F is changed by the operation unit 38, the controller 3
Numeral 9 controls the tuning frequency of the tuner 32. When the tuning frequency is F _X = 1.477 GHz,
The controller 38 has a frequency f _x = 26 corresponding to F _x
A tracking control signal TR of 2.5 kHz is generated and applied to the center conductor of the coaxial cable 50 via the band pass filter 40.

In the antenna booster circuit 10A, the frequency / voltage converter 21 converts the voltage into the tracking control voltage v _x = 5.75 V corresponding to the frequency f _x and outputs the converted voltage to the band-pass filter 13A. As a result, the bandpass filter 11A
The center frequency of the pass band is 1.477 GHz, which is the same as the tuning frequency of the tuner 32. Of the received signals of the antenna element 1, 1.47625 GHz to 1.47775
Pass only the GHz band component. If the operation by the user lowers the tuning frequency from F _x, the controller 39 sets the control to lower the tuning frequency to the tuner 32, lowering the frequency of the tracking control signal TR from f _x in conjunction with this. Therefore, the frequency of the tracking control circuit 19 /
Tracking control voltage output from the voltage converter 21 also descends from v _x, the center frequency of the band-pass filter 13A is lowered from F _x.

When the tuning operation is stopped when the tuning frequency F becomes 1.472 GHz, the controller 39 sets the frequency f of the tracking control signal TR to 250 kHz. Then, the frequency / voltage converter 21 outputs v = 5V, and the center frequency of the bandpass filter 11A is 1.472.
GHz, and among the received signals of the antenna element 1,
1.47125 GHz which is the occupied frequency band of the desired signal
Only a band component of up to 1.47275 GHz is passed. The low noise amplifier 12 amplifies the output of the band pass filter 11A. Here, even if there are many interfering stations in the band L, since the input of the low noise amplifier 12 is narrowed down to only the occupied frequency bandwidth of the desired signal for one ensemble, the interfering signal is mixed in the low noise amplifier 12. Can be avoided, and the low-noise amplifier 12 can hardly be saturated by the input of the interfering signal.
Therefore, non-linear distortion is less likely to occur, and the gain of the low-noise amplifier 12 can be increased to reduce the noise figure of the receiving system.

The output of the low noise amplifier 12 is supplied to a combiner 15
The signal is transmitted to the receiver main body 30A via the high-pass filter 22, the attenuator 18, and the coaxial cable 50, and is input to the tuner 32 via the high-pass filter 33. At this time, the presence of the attenuator 18 causes the coaxial cable 50
Is improved, and the coaxial cable 50 can be prevented from having a non-flat frequency-gain characteristic. The tuner 32 which has received the antenna reception signal performs RF amplification, tuning to a desired signal, conversion to an intermediate frequency signal, and DQPSK.
It demodulates and outputs a received data group for each carrier. The received data group is subjected to FFT conversion, parallel / serial conversion, deinterleaving on the time axis and frequency axis, and error detection / correction by the signal processing circuit 34, and the broadcast data is demodulated. When the user selects a desired program on the operation unit 38, the controller 39 controls the signal processing circuit 34 to extract, expand, and output audio data of the user desired program from the broadcast data. Therefore, a desired program of band L can be heard.

According to the above-described embodiment, the pass bandwidth of the band-pass filters 11A and 13A is set as the occupied frequency bandwidth per DAB ensemble, and the center frequency is varied in conjunction with the tuning frequency. Then, the inputs of the low noise amplifiers 12 and 14 are narrowed down to the occupied frequency bandwidth of the desired signal, and the input of the interfering signal makes it difficult for the low noise amplifiers 12 and 14 to saturate. Therefore, non-linear distortion hardly occurs, and the gains of the low noise amplifiers 12 and 14 are increased,
The noise figure of the receiving system can be reduced. As a result, the required performance of the sensitivity characteristic and noise figure of the tuner 32 can be relaxed. Further, since the attenuator 18 is provided on the power transmission end side of the coaxial cable 50, when an impedance mismatch occurs between the coaxial cable 50 and the input end of the tuner 32 which is the power receiving end of the receiver main body 30A, the combining is performed. Table 15
From the receiver 30 through the coaxial cable 50
The reflected wave component of the antenna reception signal that has traveled to the side A is reflected by the input end of the tuner 32 of the receiver main body 30A, and then returns to the combiner 15 via the coaxial cable 50 by -3.
Since it can be attenuated by dB, the coaxial cable 5
VSWR (voltage standing wave ratio) at 0 can be prevented from deteriorating, and the coaxial cable 50 can be prevented from having a non-flat frequency-gain characteristic.

Further, in the receiver main body 30A, a tracking control signal TR whose frequency changes outside the reception frequency band is generated in conjunction with the tuning frequency, and is superimposed on the coaxial cable 50 together with the DC power supply voltage, thereby forming an antenna booster. In the circuit 10A, the DC power supply voltage is taken out by the low-pass filter 17 and supplied to each section, and the tracking control circuit 19 takes out the tracking control signal TR, converts it into the tracking control voltage v, and outputs the same to the band-pass filters 11A, 11A.
3A, one coaxial cable 5
Only by laying 0, transmission of the antenna reception signal, transmission of the DC power supply voltage, and transmission of the tracking control signal can be performed, and the burden on laying the cable is greatly reduced. In addition, since the tracking control signal TR is a signal whose frequency changes in proportion to the tuning frequency, the tracking control circuit 19 can stably convert the signal to the tracking control voltage v.

In the embodiment shown in FIG. 1, the antenna element is shared by the band L and the band II-III. However, the antenna element is divided into two antenna elements dedicated to the band L and dedicated to the band II-III. You may do it. When only the band L is received, the antenna element 1 is dedicated to the band L, and the bandpass filter 13A, the low-noise amplifier 14, and the synthesizer 15 are omitted.
The output side of the low noise amplifier 12 is directly connected to the high-pass filter 2.
2 may be connected, and conversely, band II-I
When only the band II is received, the antenna element 1 is used for the band II-III and the bandpass filter 1 is used.
1A, the low noise amplifier 12, and the synthesizer 15 may be omitted, and the output side of the low noise amplifier 14 may be directly connected to the high-pass filter 22. When the coaxial cable 50 and the high-pass filter 33 are stably matched,
The attenuator 18 may be omitted, and the combiner 15 may use a type other than the diplexer.

FIG. 3 is a block diagram showing another embodiment of the present invention, and the same components as those in FIG. 1 are denoted by the same reference numerals. In the embodiment of FIG. 1, bands II and II
Although I is one reception frequency band, it is divided in FIG. 3. Further, two antenna elements for band L and band II-III are provided, and band L has relatively little interference. The pass band of the filter is fixed. In FIG. 3, reference numerals 2 and 3 denote antenna elements for bands L and II-III installed at predetermined locations in the vehicle, and 10B denotes an antenna booster circuit, of which 11 is 1.452 to 1.492 GHz. , A low-noise amplifier (LNA) 12 for amplifying the antenna reception signal passed through the band-pass filter 11, and 130A is an occupied frequency bandwidth for one ensemble of DAB. It has a pass bandwidth of 0.5 MHz and a reception frequency band of band II (8
7.5-108 MHz) band-pass filter (BPF) whose center frequency is variable by voltage control, 130B
Has a pass band width of 1.5 MHz, which is an occupied frequency bandwidth for one ensemble of DAB, and has a center frequency variable by voltage control in a band III reception frequency band (175 to 250 MHz). (BP
F), 140A is a low noise amplifier (LNA) for amplifying the antenna reception signal passed through the band-pass filter 130A,
140B is a low noise amplifier (LNA) that amplifies the antenna reception signal passed through the band-pass filter 130B, 150
Is a combiner (combiner) for combining the outputs of the low noise amplifiers 12, 140A and 140B. Here, a triplexer which is a kind of a duplexer is used.

Controller 390 of receiver body 30B
Indicates that the tuning frequency F is 87.5 MHz when receiving band II.
When the frequency changes from z to 108 MHz, a tracking control signal TR of a sine wave whose frequency changes from f _A1 = 200 kHz to f _A2 = 300 kHz in proportion to the frequency is generated. When the band III is received, the tuning frequency F is changed from 175 MHz. When the frequency changes to 250 MHz, a tracking control signal TR of a sine wave whose frequency changes from f _B1 = 500 kHz to f _B2 = 600 kHz in proportion thereto is generated. The bandpass filter (BPF) 400 provided between the controller 390 and the center conductor of the coaxial cable 50 has a frequency of 150 kHz.
It has a pass bandwidth from z to 650 kHz.

On the other hand, the tracking control circuit 190 of the antenna booster circuit 10B is connected to the input side of the attenuator 18 and has a pass band of 150 kHz to 350 kHz and a pass band of 450 kHz to 650 kHz, respectively.
The tracking control signal T when receiving bands II and III
Band-pass filter (BPF) 20 for extracting and distinguishing R
0A, 200B, and the output side of the band-pass filter 200A. When the band II is received, the tracking control signal TR is frequency-voltage converted, and the frequency of the tracking control signal TR is changed from f _A1 = 200 kHz to f _A2 = 300 k.
Hz, the band-pass filter 1 forms a tracking control voltage v _A whose voltage changes from 0V to 8V.
A frequency / voltage converter 210A for outputting to band 30A and a band II provided on the output side of bandpass filter 200B.
Upon reception of I, the tracking control signal TR is frequency-voltage converted, and the frequency of the tracking control signal TR becomes f _B1 =
While changing from 500 kHz to f _B2 = 600 kHz,
Tracking control voltage v at which voltage changes from 0V to 8V
_It has a frequency / voltage converter 210B that forms B and outputs it to the bandpass filter 130B. The low-pass filter 17 converts the DC power supply voltage transmitted by the coaxial cable 50 into low-noise amplifiers 12, 140A and 140B,
The voltage is supplied to the voltage converters 210A and 210B. The other components are configured exactly the same as in FIG.

Next, the operation of the above embodiment will be briefly described with reference to FIG. FIG. 4A is a diagram showing the relationship between the tuning frequency at the time of band II reception, the frequency of the tracking control signal, and the voltage of the tracking control voltage.
(2) is a diagram showing the relationship between the tuning frequency at the time of band III reception, the frequency of the tracking control signal, and the voltage of the tracking control voltage. The received DC power supply voltage + V ′ of the band L is sent from the receiver main body 30B to the antenna booster circuit 10B via the coaxial cable 50, and L
The PF 17 takes out the power, supplies power to each unit, and puts it in an operating state.
The band-pass filter 11 outputs an antenna reception signal of the entire band of the band L. After being amplified by the low-noise amplifier 12, the combiner 150, the high-pass filter 22, and the attenuator 1 are output.
8, transmitted to the receiver main body 30B via the coaxial cable 50. When the interference in the band L is small, the low noise amplifier 12 is hardly saturated, and the nonlinear distortion is hardly increased even if the gain is increased. When the user switches to band L using the operation unit 38 and tunes to the DAM broadcast of a certain reception frequency of band L and selects a program, the controller 390 switches the tuner 32 to band L, performs tuning control, and performs signal control. The program selection control is performed on the processing circuit 34 so that the desired program can be heard.

Reception of band II (see FIG. 4 (1)) In order for the user to listen to the DAB program broadcast at the reception frequency F of band II = 105 MHz, the user selects band II on the operation unit 38 and sets the tuning frequency F Is performed, the controller 390 controls the tuner 32 to switch to band II-III and perform tuning frequency variable control. At some point, the tuning frequency of tuner 32 is F _X = 1
When the frequency is 00 MHz, the controller 390
generates a tracking control signal TR frequency f _x = 261kHz, corresponding to _x, are applied to the central conductor of the coaxial cable 50 via the bandpass filter 400. In the antenna booster circuit 10B, the tracking control circuit 190 is used.
Extracts the tracking control signal TR superimposed on the coaxial cable 50. And
The frequency / voltage converter 210A converts the tracking control voltage v _AX corresponding to the frequency f _x to 4.88 V and outputs the converted voltage to the band-pass filter 130A. As a result, the center frequency of the pass band of the
Of the received signal of the antenna element 2 from 99.25 MHz to 100.
Pass only the 75 MHz band component. If the operation by the user raise the tuning frequency from F _x, the controller 39
0 controls the tuner 32 to increase the tuning frequency,
In conjunction with this, the frequency of the tracking control signal TR is set to f
Increase from _x . Therefore, the tracking control voltage output from the frequency / voltage converter 210A of the tracking control circuit 190 also rises from v _AX and the band-pass filter 130
The center frequency of A is increased from F _x.

When the variable operation is stopped when the tuning frequency F becomes 105 MHz, the controller 390 sets the frequency f of the tracking control signal TR to 285 kHz.
Then, the frequency / voltage converter 210A obtains v _A = 6.83.
V, the center frequency of the band-pass filter 130A becomes 105 MHz, and 104.25M which is the occupied frequency band of the desired signal among the received signals of the antenna element 2.
Only the band component from Hz to 105.75 MHz is passed.
Low noise amplifier 140A amplifies the output of bandpass filter 130A. Here, even if there are many interfering stations in band II, the input of the low noise amplifier 140A is narrowed down to only the occupied frequency bandwidth of the desired signal, so that the interfering signal is prevented from being mixed into the low noise amplifier 140A. Thus, the low-noise amplifier 140A can be hardly saturated by the input of the interference signal. Therefore, non-linear distortion hardly occurs, and the gain of the low-noise amplifier 140A can be increased to reduce the noise figure of the receiving system.

The output of the low noise amplifier 140A is
50, the high-pass filter 22, the attenuator 18, and the coaxial cable 50, are transmitted to the receiver main body 30B, are input to the tuner 32 via the high-pass filter 33, and demodulate the received data group of the DAB broadcast having the receiving frequency of 105 MHz. And output. Therefore, if the user selects a program, the desired program can be heard.

Reception of band III (see FIG. 4 (2)) The operation unit 38 allows the user to listen to the DAB program broadcast at the reception frequency F = 235 MHz of band III.
When the user selects band III and changes the tuning frequency F, the controller 390 controls the tuner 32 to switch to band II-III and perform tuning frequency variable control. At some point, the tuning frequency of tuner 32 becomes F _X
= 230 MHz, the controller 390
Generates a tracking control signal TR having a frequency f _x = 573.3 kHz corresponding to F _x ,
0 is applied to the center conductor of the coaxial cable 50. In the antenna booster circuit 10B, the band-pass filter 200B of the tracking control circuit 190 extracts the tracking control signal TR superimposed on the coaxial cable 50. Then, the frequency / voltage converter 210B changes the frequency f _x
Is converted to a tracking control voltage v _BX = 5.87 V corresponding to the bandpass filter 130A and output to the band-pass filter 130A. As a result, the center frequency of the pass band of the band-pass filter 130A becomes 230 MHz, which is the same as the tuning frequency of the tuner 32, and 229.2 of the received signals of the antenna element 2 are output.
Only the band component of 5 MHz to 230.75 MHz is passed. If the operation by the user raise the tuning frequency from F _x, the controller 390 is a control for increasing the tuning frequency to the tuner 32, in conjunction with this increasing the frequency of the tracking control signal TR from f _x. Therefore, the tracking control voltage output from the frequency / voltage converter 210B of the tracking control circuit 190 increases from even v _BX, center frequency of the band-pass filter 130B is increased from F _x.

When the variable operation is stopped when the tuning frequency F becomes 235 MHz, the controller 390 sets the frequency f of the tracking control signal TR to 580 kHz.
Then, the frequency / voltage converter 210B has v _B = 6.4 V
And the center frequency of the band-pass filter 130B is 2
35 MHz, which is 234.25 MH, which is the occupied frequency band of the desired signal among the received signals of the antenna element 2.
Pass only the band component of z to 235.75 MHz. Low noise amplifier 140B amplifies the output of bandpass filter 130B. Here, even if there are many interfering stations in band III, since the input of the low noise amplifier 140B is narrowed down to only the occupied frequency bandwidth of the desired signal, it is possible to prevent the interfering signal from being mixed into the low noise amplifier 140B. Thus, the low-noise amplifier 140B can be hardly saturated by the input of the interference signal. Therefore, non-linear distortion is less likely to occur, and the gain of the low-noise amplifier 140B can be increased to reduce the noise figure of the receiving system.

The output of the low noise amplifier 140B is
50, a high-pass filter 22, an attenuator 18, and a coaxial cable 50, are transmitted to the receiver main unit 30B, are input to a tuner 32 through a high-pass filter 33, and demodulate a DAB broadcast reception data group having a reception frequency of 235 MHz. And output. Therefore, if the user selects a program, the desired program can be heard. In the antenna booster circuit 10B, since a triplexer is used for the synthesizer 150, the degree of separation between the input terminals is high, and the outputs of the low-noise amplifiers 12, 140A and 140B enter other low-noise amplifiers, and No modulation distortion is generated.

According to the embodiment of FIG. 3, band II,
Low noise amplifiers 12 and 14 separately for band III and band L
Since 0A and 140B are provided, each low-noise amplifier can be designed to obtain characteristics such as optimum gain and noise figure for each band. When viewed in the entire receiving system, good sensitivity characteristics and noise figure can be obtained for any band. Etc. can be obtained.
Then, the pass bandwidth of the band-pass filters 130A and 130B is set as the occupied frequency bandwidth per ensemble of the DAB, and the center frequency is changed in conjunction with the tuning frequency, so that the inputs of the low noise amplifiers 140A and 140B are input. The frequency band occupied by the desired signal is narrowed down, and the low-noise amplifiers 140A and 140B are less likely to be saturated by the input of the interfering signal. Therefore, non-linear distortion hardly occurs, and the gain of the low-noise amplifiers 140A and 140B can be increased to reduce the noise figure of the receiving system at the time of receiving the bands II and III. Although the pass band of the band-pass filter 11 is fixed to the whole band L, the low-noise amplifier 12 hardly saturates in the band L because there are few interfering signals. Therefore, the gain of the low noise amplifier 12 is increased and the band L
The noise figure of the receiving system at the time of reception can be reduced.
As a result, the required performance of the sensitivity characteristic and noise figure of the tuner 32 can be relaxed.

In the embodiment of FIG. 3, the band II
And III share the antenna element. However, the antenna element may be divided into two antenna elements dedicated to band II and dedicated to band III. When only the bands II and III are received, the antenna element 2, the band-pass filter 11, and the low-noise amplifier 12 may be omitted, and the combiner 50 may be changed to a 2-input / 1-output type. When only band II is received, antenna element 3 is dedicated to band II, and antenna element 2, band-pass filter 11, low-noise amplifier 12, band-pass filter 130B, low-noise amplifier 140B, combiner 150, band-pass filter 200B, the frequency / voltage converter 210B may be omitted, and the output of the low noise amplifier 140A may be directly input to the high-pass filter 22. When the coaxial cable 50 and the high-pass filter 33 are stably matched, the attenuator 18 can be omitted, and the combiner 150 may be of a type other than the triplexer. In each of the embodiments shown in FIGS.
Although AB has been described as an application example, the present invention is not limited to this, and can be applied to a receiver for another broadcast system.

[0043]

According to the receiver with the antenna booster of the present invention, the input of the low-noise amplifier of the antenna booster circuit is changed to the occupied frequency of the desired signal even if the reception frequency band is wide and there are many interfering stations. Since it can be narrowed down to only the bandwidth, it is possible to prevent interference signals from being mixed into the low noise amplifier,
The low noise amplifier can be hardly saturated by the input of the interference signal. Therefore, non-linear distortion hardly occurs, and the gain of the low-noise amplifier can be increased to reduce the noise figure of the receiving system. As a result, the sensitivity characteristics and noise figure performance conditions required for the tuner of the receiver body can be relaxed, and the configuration can be simplified and inexpensive.

[Brief description of the drawings]

FIG. 1 is an in-vehicle DAB according to one embodiment of the present invention.
It is a block diagram of a receiver.

FIG. 2 is a diagram showing a relationship between a tuning frequency and a tracking control signal and a tracking control voltage.

FIG. 3 is a block diagram of an in-vehicle DAB receiver according to another embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between a tuning frequency and a tracking control signal and a tracking control voltage.

FIG. 5 is a block diagram showing a configuration example of a vehicle-mounted DAB receiver according to the related art.

[Explanation of symbols]

1, 2, 3 antenna elements 10A, 10B
Antenna booster circuits 11, 13, 130A, 130B, 20, 40, 200
A, 200B, 400 band-pass filters 17, 41 Low-pass filters 12, 14, 140A, 140B Low-noise amplifiers 18 Attenuators 19, 190 Tracking control circuits 21, 210A, 210B Frequency / voltage converters 22, 33 High-pass filters 30A, 30B
Receiver main unit 32 Tuner 33 High-pass filter 34 Signal processing circuit 39, 390 Controller 50 Coaxial cable

Claims (3)

(57) [Claims] 1. A receiver with an antenna booster in which an antenna booster circuit and a receiver main body are connected by a transmission cable, wherein an input side is connected to an antenna element to the antenna booster circuit, and an occupied frequency bandwidth of a desired signal is defined as a pass bandwidth. A band-pass filter whose center frequency is variable within the reception frequency band, a low-noise amplifier to which the output of the band-pass filter is input , and an antenna provided between the output side of the low-noise amplifier and the transmission cable.
A receiver with an antenna booster, comprising: an antenna booster; and a tracking control circuit for variably controlling the center frequency of a filter in conjunction with a change in tuning frequency on the receiver body side. 2. A receiver with an antenna booster in which an antenna booster circuit and a receiver main body are connected by a transmission cable, wherein the antenna booster circuit is provided for each reception frequency band, and an input side is connected to an antenna element. A band-pass filter having at least one having the same pass bandwidth as the occupied frequency bandwidth of the desired signal, having a variable center frequency within the receive frequency band, and having the receive frequency band having a fixed pass band; A plurality of low-noise amplifiers individually provided on the output side of the pass filter; a combiner for receiving the output of each low-noise amplifier, the output side being connected to a transmission cable; and a receiver having a center frequency variable. While receiving the reception frequency band corresponding to the band-pass filter, the center frequency for the band-pass filter can be Receiver with antenna booster, characterized in that it and a tracking control circuit for the control. 3. Between the output side of the synthesizer and the transmission cable
3. The receiver with an antenna booster according to claim 2 , further comprising an attenuator .