JPH1022856A - Broadcast receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broadcast receiver in a comparatively simple constitution which can perform the frequency conversion of the audio 1st intermediate frequency signal outputted from a TV tuner at a low cost and. SOLUTION: This receiver includes a TV tuner 2 which converts the received TV broadcast into an audio 1st intermediate-frequency signal in terms of frequency, a 1st frequency converter 7 which converts the audio 1st intermediate- frequency signal into an audio 2nd intermediate-frequency signal in terms of frequency, and an FM tuner 1 which converts the received FM radio broadcast into an FM intermediate-frequency signal via a 2nd frequency converter 1b in terms of frequency. Then the frequency control is applied via a common phase control loop 1e to a local oscillator 7b, constructing the converter 7 and a local oscillator 1d constructing the converter 1b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broadcast receiver, and more particularly to a television receiver for receiving a television broadcast, receiving an FM radio broadcast with an FM tuner, and reproducing both audio signals in a common reproduction stage. The present invention relates to a broadcast receiver that selectively reproduces a broadcast by using the broadcast receiver.

[0002]

2. Description of the Related Art Conventionally, in a broadcast receiver that receives FM broadcasts and receives audio signals of television broadcasts, FM radio broadcasts are individually transmitted by FM tuners, and audio signals of television broadcasts are individually transmitted by television tuners. The audio signals received by these tuners are subjected to processing such as demodulation and amplification, and are output from a common speaker or the like.

FIG. 4 is a block diagram showing an example of such a conventional broadcast receiver.

[0004] As shown in FIG.
FM tuner 4 connected to M radio broadcast receiving antenna
1, a television tuner 42 connected to the television broadcast receiving antenna, an FM detection circuit 43 connected to the output of the FM tuner 41, a stereo demodulation circuit 44 connected to the output of the FM detection circuit 43, An amplification circuit 45 connected to each output of the demodulation circuit 44 and a multiplex demodulation circuit 49 described later; a speaker 46 connected to the output of the amplification circuit 45; and a television audio signal frequency connected to the output of the television tuner 42. A converter 47, a television audio signal detection circuit 48 connected to the output of the television audio signal frequency converter 47, a multiplex demodulation circuit 49 connected to the output of the television audio signal detection circuit 48, and a television tuner. 42, and a display unit 51 connected to the video signal circuit 50. To have.

In this case, the FM tuner 41 comprises an FM tuning circuit 41a, a frequency mixer 41c, a local oscillator 41
and a frequency converter 41 comprising a phase control loop 41e.
b and are connected as shown in FIG. The television audio signal frequency converter 47 includes a frequency mixer 47.
a, a local oscillator 47b, and a crystal oscillator 47c for defining the oscillation frequency of the local oscillator 47b, which are connected as shown in FIG.

[0006] The broadcast receiver shown in FIG. 4 operates roughly as follows.

At the time of receiving an FM radio broadcast, the FM radio broadcast signal received by the FM tuning circuit 41a is frequency-converted by a frequency converter 41b, and a frequency of 10.7 MHz is transmitted.
It is output as an M intermediate frequency signal. This FM intermediate frequency signal is detected by an FM detection circuit 43 and demodulated into a stereo audio signal by a stereo demodulation circuit 44. Next, the stereo audio signal is amplified by the amplifier circuit 45 and output from the speaker 46.

On the other hand, at the time of receiving a television broadcast, the audio signal of the television broadcast received by the television tuner 42 is taken out as an audio first intermediate frequency signal of 54.25 MHz, and a television audio signal frequency converter 47 is provided. , And is output as an audio second intermediate frequency signal of 10.7 MHz. The audio second intermediate frequency signal is detected by the audio detection circuit 48,
The signal is demodulated into a television audio signal by the multiplex demodulation circuit 49. Next, the television audio signal is amplified by the amplifier circuit 45 similarly to the FM stereo audio signal, and is output from the speaker 46.

[0009]

In the conventional broadcast receiver, the television audio signal frequency converter 47 converts the 54.25 MHz audio first intermediate frequency signal into one.
In order to regulate the oscillation frequency of the local oscillator 47b when the frequency is converted to the audio second intermediate frequency signal of 0.7 MHz, a relatively expensive quartz oscillator 47c is used for the television audio signal frequency converter 47. Therefore, the manufacturing cost of the television audio signal frequency converter 47 increases,
As a result, there is a problem that the manufacturing cost of the broadcast receiver increases.

An object of the present invention is to solve such a problem, and an object of the present invention is to realize frequency conversion for an audio first intermediate frequency signal output from a television tuner with a low-cost and relatively simple configuration. It is an object of the present invention to provide a broadcast receiver.

[0011]

In order to achieve the above object, a broadcast receiver according to the present invention converts an audio first intermediate frequency signal of a television broadcast output from a television tuner into an audio second intermediate frequency signal. When performing frequency conversion, F
There is provided means for sharing part (only the PLL) or all of the frequency converter for frequency-converting the M radio broadcast signal.

If this means is adopted, it is not necessary to use a relatively expensive crystal oscillator for the frequency converter when the frequency of the audio first intermediate frequency signal is converted to the audio second intermediate frequency signal. The manufacturing cost of the receiver, that is, the broadcast receiver, is reduced, and the circuit configuration of the broadcast receiver is simplified by also using the frequency converter.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment of the present invention, a broadcast receiver comprises a television tuner for converting a received television broadcast into an audio first intermediate frequency signal, and a television tuner for converting the audio first intermediate frequency signal. A first frequency converter for frequency-converting the audio to a second intermediate frequency signal;
An FM tuner for frequency-converting a radio broadcast into an FM intermediate frequency signal by a second frequency converter, wherein a first local oscillator forming a first frequency converter and a second local oscillator forming a second frequency converter are provided. The frequency is controlled by a common phase control loop.

[0014] In another embodiment of the present invention,
The broadcast receiver includes a television tuner that frequency-converts a received television broadcast into an audio first intermediate frequency signal, and a frequency converter that converts the received FM radio broadcast into frequency signals.
An FM tuner for converting the frequency into an M intermediate frequency signal, and selectively supplying an audio first intermediate frequency signal to the frequency converter when receiving a television broadcast, and converting the frequency into an audio second intermediate frequency signal there. Is what you do.

In a preferred embodiment of the present invention, the frequency converter includes a local oscillator whose frequency is controlled by a phase control loop, wherein the local oscillator receives the first intermediate frequency signal when receiving a television broadcast. Output a local oscillation signal having a high frequency.

According to one embodiment of the present invention, the first
Since the first local oscillator forming the frequency converter and the second local oscillator forming the second frequency converter are frequency-controlled by a common phase control loop, the oscillation frequency of the first local oscillator is stabilized. Therefore, it is not necessary to use a crystal oscillator, and as a result, the manufacturing cost of the first frequency converter, that is, the manufacturing cost of the broadcast receiver can be reduced.

According to another embodiment of the present invention,
Since the whole of the first frequency converter in the above embodiment is also used as the second frequency converter, it is not necessary to separately provide the first frequency converter, and as a result, manufacturing of the first frequency converter Not only the cost, that is, the manufacturing cost of the broadcast receiver can be significantly reduced, but also the circuit configuration of the broadcast receiver can be significantly simplified.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

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

[0020] As shown in FIG.
An FM tuner 1 connected to an M broadcast receiving antenna, a television tuner 2 connected to a television broadcast receiving antenna, and an FM connected to an output of the FM tuner 1
The detection circuit 3, a stereo demodulation circuit 4 connected to the output of the FM detection circuit 3, an amplification circuit 5 connected to each output of the stereo demodulation circuit 4 and a multiplex demodulation circuit 9 described later, and an output of the amplification circuit 5. A connected speaker 6, a television audio signal frequency converter 7 connected to the output of the television tuner 2, and a television audio signal frequency converter 7
Audio detection circuit 8 connected to the output of
And a multiplex demodulation circuit 9 connected to the output of
Illustration of a video signal circuit and a display unit connected to the output of the television tuner 2 is omitted.

The FM tuner 1 has an FM tuning circuit 1
a, a frequency mixer 1c, a local oscillator 1d, and a frequency converter 1b including a phase control loop 1e. The frequency mixer 1c and the local oscillator 1d are connected, and the local oscillator 1d, the phase control loop 1e, Are connected in a loop. The television audio signal frequency converter 7 includes a frequency mixer 7a and a local oscillator 7b. The frequency mixer 7a and the local oscillator 7b are connected, and the local oscillator 7b and the phase control loop 1e are connected in a loop. Have been. The phase control loop 1e is configured to be shared between the local oscillator 1d of the frequency mixer 1c and the local oscillator 7b of the television audio signal frequency converter 7.

The broadcast receiver of the first embodiment shown in FIG. 1 operates as follows.

At the time of receiving the FM radio broadcast, the FM radio broadcast received by the FM tuning circuit 1a is frequency-converted by the frequency converter 1b, and the frequency of the FM radio broadcast is 10.7 MHz.
Output as an intermediate frequency signal. The FM intermediate frequency signal is detected by an FM detection circuit 3 and demodulated by a stereo demodulation circuit 4 into an FM stereo audio signal.
Next, the FM stereo audio signal is amplified by the amplifier circuit 5 and output from the speaker 6.

On the other hand, at the time of receiving a television broadcast, the audio signal of the television broadcast received by the television tuner 2 is taken out as an audio first intermediate frequency signal of 54.25 MHz, and a television audio signal frequency converter is provided. Frequency converted by 7 and 10.7MHz
Is output as the audio second intermediate frequency signal. The audio second intermediate frequency signal is detected by an audio detection circuit 8 and demodulated by a multiplex demodulation circuit 9 into a television audio signal. Next, the television audio signal is amplified by the amplifier circuit 5 like the FM stereo audio signal, and is output from the speaker 6.

FIG. 2 is an explanatory diagram showing the relationship between various frequencies such as FM radio broadcast signals and television broadcast signals in major countries.

First, the case where the broadcast receiver of the first embodiment is applied in Japan will be described.

The frequency range of 76 MHz to 90 MHz band F
When receiving an M radio broadcast, a desired tuning signal is supplied to the phase control loop 1e, and the local oscillation frequency of the local oscillator 1d is controlled to be higher than the FM intermediate frequency 10. A lower local oscillation signal of 65.3 MHz to 79.3 MHz which is lower by 7 MHz is generated. At this time, in the frequency mixer 1c, the 76 MHz to 90 MHz FM reception signal supplied from the FM tuning circuit 1a is mixed with the local oscillation signal generated by the local oscillator 1d, and the output thereof is 10.7 MHz.
An FM intermediate frequency signal of z is output.

On the other hand, when the frequency is 90 MHz to 108 MH
When receiving a television broadcast in a band of at least z and 170 MHz, the television tuner 2 converts the television reception signal into a 54.25 MHz audio first intermediate frequency signal, and then under the control of the phase control loop 1e. In the local oscillator 7b, 64.9 higher than 54.25 MHz by the audio second intermediate frequency 10.7 MHz.
An upper local oscillation signal of 5 MHz is generated. At this time,
In the frequency mixer 7a, the television tuner 2
Is mixed with the upper local oscillation signal supplied from the local oscillator 7b, and the 10.7 MHz audio second intermediate frequency signal is output to the output.

Next, a case where the broadcast receiver of the first embodiment is applied in the United States will be described.

When receiving an FM radio broadcast in the frequency band of 88 MHz to 108 MHz, a desired tuning signal is supplied to the phase control loop 1e, and the local oscillation frequency of the local oscillator 1d is controlled by the phase control loop 1e. 88 MHz
FM intermediate frequency 10.7MHz than 108MHz
And generates an upper local oscillation signal of 98.7 MHz to 118.7 MHz, which is higher than that of the first embodiment. At this time, the frequency mixer 1c
, The 88 MH supplied from the FM tuning circuit 1 a
z to 108 MHz FM reception signal and local oscillator 1d
Is mixed with the local oscillation signal where
A 0.7 MHz FM intermediate frequency signal is output.

The frequency is between 54 MHz and 88 MHz.
When receiving a television broadcast in the band of 174 MHz or more, the television tuner 2 converts the television reception signal into a first intermediate frequency signal of 49.25 MHz audio, and then controls the local area under the control of the phase control loop 1e. In the oscillator 7b, 59.95 which is higher than 49.25 MHz by the audio second intermediate frequency 10.7 MHz.
An upper local oscillation signal of MHz is generated. At this time, in the frequency mixer 7a, the audio first intermediate frequency signal supplied from the television tuner 2 and the local oscillator 7
The upper local oscillation signal supplied from b is mixed, and a 10.7 MHz audio second intermediate frequency signal is output at the output.

Next, a case where the broadcast receiver of the first embodiment is applied in Europe will be described.

When receiving an FM radio broadcast in the frequency band of 88 MHz to 108 MHz, a desired tuning signal is supplied to the phase control loop 1e, and the local oscillation frequency of the local oscillator 1d is controlled by the phase control loop 1e. 88MH
FM intermediate frequency 10.7MH from z to 108MHz
An upper local oscillation signal of 98.7 MHz to 118.7 MHz higher by z is generated. At this time, the frequency mixer 1
c, the 88M supplied from the FM tuning circuit 1a
Hz to 108 MHz FM reception signal and local oscillator 1
d is mixed with the local oscillation signal, and 1 is output to the output.
A 0.7 MHz FM intermediate frequency signal is output.

The frequency is between 44 MHz and 68 MHz.
When receiving a television broadcast in a band of 174 MHz or more, the television tuner 2 converts the television reception signal into an audio first intermediate frequency signal of 33.4 MHz, and then, under the control of the phase control loop 1e,
The local oscillator 7b generates an upper local oscillation signal of 44.1 MHz higher than 33.4 MHz by the audio second intermediate frequency 10.7 MHz. At this time, in the frequency mixer 7a, the audio first intermediate frequency signal supplied from the television tuner 2 and the upper local oscillation signal supplied from the local oscillator 7b are mixed, and the output thereof is 1
An audio second intermediate frequency signal of 0.7 MHz is output.

As described above, the broadcast receiver of the first embodiment sets the local oscillation frequency of the local oscillator 1d to the frequency of the FM radio broadcast in accordance with the frequency of the FM radio broadcast received by the FM tuner 1. If the frequency is selectively set to the upper oscillation frequency or the lower oscillation frequency, it becomes possible to receive FM broadcast signals and television broadcast signals of many countries while minimizing image disturbance.

According to the broadcast receiver of the first embodiment, the television audio signal frequency converter 7 converts the audio first intermediate frequency signal output from the television tuner 2 into an audio second intermediate frequency signal. In order to stabilize the oscillation frequency of the local oscillator 7b, the phase control loop 1e used for the frequency converter 1b of the FM tuner 1 is also used instead of using a crystal oscillator, The manufacturing cost of the converter 7, that is, the manufacturing cost of the broadcast receiver can be reduced.

FIG. 3 is a block diagram showing a second embodiment of the broadcast receiver according to the present invention.

In FIG. 3, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

The difference between the second embodiment and the first embodiment is that the configuration of the television audio signal frequency converter 7 is different from that of the first embodiment. , Ie, the phase control loop 1e is also used as the frequency converter 1b side, whereas the second embodiment has the entire configuration of the television audio signal frequency converter 7, ie, the frequency mixer 1c. The local oscillator 1d and the phase control loop 1e are also used as those of the frequency converter 1b, and the first embodiment differs from the first embodiment in that an audio detection circuit 8 and a multiplex demodulation circuit are provided on the output side of the television audio signal frequency converter 7. 9, the buffer amplifier 10 is connected between the output of the television tuner 2 and the input of the frequency mixer 1c in the second embodiment, and the buffer amplifier 10 is connected to the output side of the frequency converter 1b. Audio detection circuit 8 The only difference is that the audio second intermediate frequency signal processing circuit 11 including the multiplex demodulation circuit 9 is connected and arranged. In addition, the difference in configuration between the first embodiment and the second embodiment is as follows. Absent.

The operation of the second embodiment is similar to the operation of the first embodiment, except that when receiving a television broadcast, the television audio signal frequency converter 7 of the first embodiment converts the audio first intermediate frequency signal into the audio second intermediate frequency. The point that all the frequency conversion operations into signals are performed by the frequency converter 1b on the FM tuner 1 side, and the detection and multiplex demodulation of the audio second intermediate frequency signal output from the frequency converter 1b and the audio demodulation are performed by the audio intermediate frequency signal processing. The other operations are almost the same as those of the first embodiment except for the operation performed by the circuit 11.

As described above, according to the broadcast receiver of the second embodiment, the television audio signal frequency for frequency-converting the audio first intermediate frequency signal output from the television tuner 2 into the audio second intermediate frequency signal. Since the frequency converter 1b of the FM tuner 1 is also used as the converter, the manufacturing cost of the television audio signal frequency converter 7, that is, the manufacturing cost of the broadcast receiver can be reduced. The circuit configuration of the machine can be significantly simplified.

[0042]

As described above, according to the first aspect of the present invention, the first audio output from the television tuner is output.
When the intermediate frequency signal is frequency-converted into the audio second intermediate frequency signal by the first frequency converter, the second local oscillator in the FM tuner is used to stabilize the oscillation frequency of the first local oscillator constituting the first frequency converter. The second part of the frequency converter
Since the phase control loop for controlling the local oscillator is also used, it is not necessary to use a crystal oscillator for stabilizing the oscillation frequency of the first local oscillator, and the manufacturing cost of the first frequency converter, that is, There is an effect that the manufacturing cost of the broadcast receiver can be reduced.

According to the second aspect of the present invention, when the audio first intermediate frequency signal output from the television tuner is frequency-converted into the audio second intermediate frequency signal,
Since the frequency converter in the FM tuner is also used, it is not necessary to separately provide a dedicated frequency converter, and the manufacturing cost of the frequency converter, that is, the manufacturing cost of the broadcast receiver can be significantly reduced. This has the effect that the circuit configuration of the broadcast receiver can be significantly simplified.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing frequencies of TV broadcasting and FM radio broadcasting in major countries.

FIG. 3 is a block diagram showing a second embodiment of the broadcast receiver according to the present invention;

FIG. 4 is a block diagram showing an example of a conventional broadcast receiver.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 FM tuner 1 a FM tuning circuit 1 b frequency converter (second frequency converter) 1 c frequency mixer 1 d local oscillator 1 e phase control loop 2 television tuner 7 television audio signal frequency converter (first frequency converter) 7 a frequency Mixer 7b Local oscillator

Claims (3)

[Claims] 1. A television tuner for frequency-converting a received television broadcast to an audio first intermediate frequency signal, and a first frequency converter for frequency-converting the audio first intermediate frequency signal to an audio second intermediate frequency signal. , Received F
An FM tuner for frequency-converting the M radio broadcast into an FM intermediate frequency signal by a second frequency converter; a first local oscillator forming the first frequency converter; and a second local oscillator forming the second frequency converter A broadcast receiver wherein the frequency of an oscillator is controlled by a common phase control loop. 2. A television tuner for frequency-converting a received television broadcast into an audio first intermediate frequency signal, and a frequency converter for converting the received FM radio broadcast into frequency signals.
And an FM tuner for converting the frequency into an M intermediate frequency signal.
A broadcast receiver, wherein an intermediate frequency signal is selectively supplied to the frequency converter and frequency-converted into an audio second intermediate frequency signal. 3. The frequency converter includes a local oscillator that is frequency controlled by a phase control loop, the local oscillator having a higher frequency than the first intermediate frequency signal when receiving a television broadcast. The broadcast receiver according to claim 2, wherein the broadcast receiver outputs a signal.