JPH06334554A - Television tuner unit - Google Patents

Abstract

PURPOSE:To provide the television tuner unit which facilitates adjustments in manufacture processes including even a sound multiplexing circuit and has stable performance. CONSTITUTION:A tuner part 101 including a high frequency circuit and a mixer circuit, a video and sound intermediate frequency circuit 102 including a video intermediate frequency amplifying circuit, a video detecting circuit, a sound detecting circuit, a sound intermediate amplification frequency circuit, and an FM demodulating circuit, and a sound multiplexing circuit part 103 are incorporated in a single shield block housing 100. The intermediate frequency circuit part 102 and sound multiplexing circuit part 103, and tuner part 101 and intermediate frequency circuit part 102 are connected directly to each another in the housing 100.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a television receiver and a VT.
The present invention relates to a TV tuner unit built in the R.

[0002]

2. Description of the Related Art A television tuner for receiving a television signal is not only a television receiver but also a VTR.
In order to make it easy to add a function of receiving a television signal to the device or other video equipment, the circuit block is configured as a unit.

FIG. 3 is a block diagram of an example of a conventional television receiver. That is, in FIG. 3, 1 is a TV tuner unit, 2 is a channel selection control circuit composed of a microcomputer, 3 is a video and audio intermediate frequency circuit block, 4 is a video processing circuit, 5 is an audio multiplexing circuit, and 6 is an audio processing circuit. is there.

The television tuner unit 1 includes a high frequency circuit 11 and a mixer circuit 12, and selects a tuning control circuit 2 from a television broadcast wave received by an antenna 7.
A broadcast wave signal of a desired broadcast channel is tuned by the channel selection signal from, and the signal is converted into an intermediate frequency signal and supplied to the video and audio intermediate frequency circuit 3. Further, the tuning control circuit 2 receives a signal for auto fine tuning from the intermediate frequency circuit block 3 and performs control so that the tuning state of the television tuner unit 1 becomes appropriate.

The video and audio intermediate frequency circuit block 3 is
Video intermediate frequency amplification circuit 31 and video detection circuit 32, audio detection circuit 33, audio intermediate frequency circuit 34 and FM
A demodulation circuit 35 is included. The video signal obtained by the video detection is supplied to the video processing circuit unit 4, and its output is supplied to the CRT display 8 to reproduce the image.

Further, the FM demodulation output from the circuit block 3 is supplied to the audio multiplexing circuit 5, and when it is not audio multiplex broadcasting, a monaural signal is passed through the audio processing circuit 6 and
It is supplied to the speakers 9L and 9R for monaural reproduction. When the audio multiplex broadcasting is stereo broadcasting, the audio signal outputs of the left and right channels are obtained from the audio multiplex circuit 5, and these are supplied to the speakers 9L and 9R via the audio processing circuit 6 for stereo reception. The sound is played.

In the case of bilingual broadcasting, the audio multiplexing circuit 5 extracts the main audio signal and the sub audio signal and reproduces them by the speakers 9L and 9R, respectively. In the case of voice multiplexing in the United States, a voice signal of a second audio program (hereinafter referred to as SAP) is sent and can be reproduced by the speakers 9L and 9R via the voice processing circuit 6.

The audio multiplexing circuit 5 is provided with a mode selector switch for selecting a program such as a stereo reproduction mode, a bilingual broadcasting mode, and a SAP mode. The audio multiplexing circuit 5 is also provided with an output terminal for controlling lighting of an LED (light emitting diode) which serves as an indicator for stereo broadcast reception, bilingual broadcast reception, and SAP reception.

[0009]

As described above, the conventional TV tuner unit includes only the high frequency circuit and the mixer circuit, and is separate from the video and audio intermediate frequency circuit block 3 and the audio multiplexing circuit 5. It was the one.
However, some TV tuner units include the intermediate frequency circuit block 3 as well, but even in that case,
It was a separate body from the voice multiplexing circuit 5.

For this reason, the adjustment of the audio multiplex circuit 5 is performed independently of the television tuner unit, the video and audio intermediate frequency circuit block 3, and the like.

However, the characteristics of the voice multiplexing circuit 5 are:
The output level of the TV tuner unit 1 in the previous stage,
Since it affects the output level of the intermediate frequency circuit block 3,
There is an inconvenience that the adjustment is performed in two stages, such as performing adjustment for each circuit unit independently, assembling each circuit unit as a set, and then performing readjustment again.

In addition, when each circuit unit is assembled into a set, since each circuit unit exists in a separate space within the set, it is difficult to ensure the stability of performance due to the difference in conditions such as temperature and power supply. It was Since the operation and performance are determined after the assembly as a set, there is a limit to rationalization of the mass production process and reduction of the defective rate.

For example, FIG. 4 shows a block diagram focusing on the adjustment in the audio multiplexing circuit 5. That is, as shown in FIG. 4, F of the video and audio intermediate frequency circuit block 3 is
The M demodulation output is the input level adjusting means 5 of the voice multiplexing circuit 5.
1 is input to the filter circuit 52.

The filter circuit 52 has a main audio signal and
It is for separating the sub audio signal, and is configured such that the filter characteristic is adjusted by the filter characteristic adjusting means 53. With this filter circuit 52,
The audio multiplexing circuit 5 has a matrix circuit 54. The matrix circuit 54 obtains left and right channel audio signals when the audio multiplexed signal is a stereo signal, and obtains a main audio signal and a sub audio signal when the audio multiplexed signal is bilingual multiplexed broadcasting. The adjustment of the separation in this case is performed by the adjusting means 55.

However, the adjustment by the filter characteristic adjusting means 53 and the adjustment by the separation adjusting means 55 are
It depends on the input level. Therefore, even if the input level adjusting means 51 makes an adjustment once, if the output level of the circuit block 3 at the preceding stage changes, readjustment becomes necessary. Since the circuit block 3 and the voice multiplexing circuit 5 are separate units, the above readjustment is necessary when the environment changes, and generally after assembly,
It is necessary to readjust in the manufacturing process.

The present invention is intended to provide a television tuner unit capable of eliminating the above drawbacks.

[0017]

In order to solve the above problems, according to the present invention, when the reference numerals of the embodiments described later are made to correspond to each other, a high frequency circuit and a mixer circuit are provided in a single shield block housing 100. Tuner section 101 including
And a video and audio intermediate frequency circuit section 102 including a video intermediate frequency amplification circuit, a video detection circuit and an audio detection circuit, an audio intermediate amplification frequency circuit, and an FM demodulation circuit, and an audio multiplexing circuit section 10.
3 is built in and has an integrated structure, and is provided between the intermediate frequency circuit section 102 and the audio multiplex circuit section 103, and between the tuner section 101 and the intermediate frequency circuit section 102.
The space between and is directly connected inside the housing 100.

[0018]

According to the television tuner unit of the present invention having the above-described structure, even an audio multiplex circuit, which is conventionally a separate circuit block, is housed in one shield block housing, and these circuits are provided in the same space. The temperature characteristics and the power supply conditions are equalized due to the existence of, and the performance is stabilized.

Further, since the tuner section, the intermediate frequency circuit section, and the audio multiplex circuit section are present in the unit, filter adjustment and separation adjustment in the audio multiplex circuit section can be performed at the adjustment stage of this unit. Since the input level of the multiplex circuit unit does not change, the adjustment only needs to be done once.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a television tuner unit according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of the television tuner unit of this example. In FIG. 1, reference numeral 100 denotes a shield block housing of the TV tuner unit of this example. Inside the housing 100, the TV tuner 1, the video and audio intermediate frequency circuit 3, and the audio multiplexing circuit shown in FIG. Each circuit block 5 is built in.

That is, in FIG. 1, 101 is a television tuner unit, which includes a high frequency circuit and a mixer circuit. Reference numeral 102 denotes a video and audio intermediate frequency circuit section, which includes a video intermediate frequency amplification circuit, a video detection circuit, an audio detection circuit, an audio intermediate frequency amplification circuit, and an FM demodulation circuit. Further, 103 is a voice multiplexing circuit unit.

In the case of this example, these respective circuit parts 101, 1
02 and 103 are formed on the same substrate 104. Reference numeral 105 is an input terminal for the RF signal received by the antenna.

The tuner section 101 and the intermediate frequency circuit section 102 are directly connected to each other, and the intermediate frequency circuit section 102 and the audio multiplex circuit section 103 are directly connected to each other. Similarly, the input and output of the tuner unit 101 and the intermediate frequency circuit unit 102 are also directly connected in this example.

The terminal 21 derived from the unit case 100 is derived from the tuner unit 101 and is a terminal for connection with the tuning control circuit (CPU) 2 shown in FIG. Further, the terminal 22 derived from the housing 100 is derived from the video and audio intermediate frequency circuit section 102, which is connected to the channel selection control circuit section 2 and the video processing circuit 4 in FIG. For connection.

Furthermore, the terminal 2 led out from the housing 100
3 is derived from the audio multiplexing circuit unit 103, which is a terminal for connection with the audio processing circuit 6 in FIG. 3 and other circuits.

As an example of the terminal 23, a is a stereo indicator display terminal, b is an SAP indicator display terminal, c and d are left and right channel stereo audio signal output terminals and an SAP output terminal by audio switching, e
Is a voice multiple output mode switching terminal, and f is a muting terminal.

The presence of the terminal 23 relating to the voice multiplexing circuit is as follows.
This means that the TV tuner unit is equipped with a sound multiplex indicator display terminal and a sound multiplex output switching terminal.
When used as a tuner unit of other video equipment with a built-in television tuner, it is possible to easily equip the video equipment with a receiving unit compatible with audio multiplexing.

In this case, it becomes possible to connect a necessary terminal among the terminals 23 as an input / output of the microcomputer for controlling the TV tuner unit, and the control signal for the audio multiplex circuit is also output from the microcomputer for the TV tuner unit. Can be handled as a control signal of the audio multiplexing circuit, and the mode control of the audio multiplexing circuit and other controls can be facilitated.

As described above, since the audio multiplex circuit unit 103 is also incorporated and integrated in the shield block housing 100 as the TV tuner unit, the adjustment is performed in comparison with each circuit unit. As a TV tuner unit, it only needs to be done once, and the adjustment work is extremely easy.

Further, since each circuit portion 101, 102, 103 is housed in a common casing 100 and is unitized,
Temperature characteristics and power supply conditions are also equalized, performance is stable,
The defective rate is lowered.

Further, in this case, since the television tuner unit includes the audio multiplex decoder function, the audio multiplex control, the mode display, and the output of the stereo or second audio program can be obtained from the television tuner unit. There is a merit that the usability as a TV tuner unit is improved, such that a receiving device compatible with audio multiplex broadcasting can be easily configured.

FIG. 2 shows another example of the television tuner unit according to the present invention. In this example, the tuner unit 101, the video and audio intermediate frequency circuit unit 102, and the audio multiplexing circuit unit 103 are separate boards 111 and 112, respectively.
It is formed in 113. Then, between the tuner unit 101 and the intermediate frequency circuit unit 102 and the intermediate frequency circuit unit 1
02 and the audio multiplex circuit unit 103, a connector 121
And 122 are directly connected.

In this way, each circuit section 101, 102, 1
By adopting a structure in which 03 is a separate substrate and is connected by the connectors 121 and 122, the versatility of the television tuner unit can be increased. That is, for example, a TV tuner unit compatible with various audio multiplex systems such as a TV tuner unit for Japan, a tuner unit for audio multiplex systems for the United States, a German audio multiplex system, etc. should be provided with appropriate circuit parts. Can be easily configured by appropriately replacing.

[0035]

As described above, according to the present invention, the tuner section, the intermediate frequency circuit section, and the audio multiplexing circuit, which have conventionally existed as separate circuit blocks inside the single shield block housing, are provided. With the built-in part,
Since these circuit parts are made to exist in the same environment, adjustment is only required once, and temperature characteristics and power supply conditions are constant, so performance is stable, streamlining the mass production process and reducing the defect rate. Contribute.

Since the television tuner unit also includes an audio multiplex circuit, the television tuner unit alone can switch the indicator operation for stereo output display, and also can switch the audio multiplex mode. There is a merit that it will be possible.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a television tuner unit according to the present invention.

FIG. 2 is a block diagram of another embodiment of the television tuner unit according to the present invention.

FIG. 3 is a block diagram of a configuration example of a television receiver.

FIG. 4 is a diagram for explaining adjustment of an audio multiplexing circuit.

[Explanation of symbols]

 100 shield block housing 101 tuner section 102 video and audio intermediate frequency circuit section 103 audio multiplex circuit section 105 common board 111-113 board 121, 122 connector

Claims (4)

[Claims] 1. A tuner unit including a high frequency circuit and a mixer circuit in a single shield block housing, a video intermediate frequency amplification circuit, a video detection circuit and an audio detection circuit, an audio intermediate amplification frequency circuit, and an FM demodulation circuit. A video and audio intermediate frequency circuit section including an audio multiplexing circuit section and an audio multiplexing circuit section are built in and integrated structure, and between the intermediate frequency circuit section and the audio multiplexing circuit section and between the tuner section and the intermediate section. A television tuner unit in which the frequency circuit section is directly connected inside the housing. 2. The television tuner unit according to claim 1, wherein the tuner section, the intermediate frequency circuit section, and the audio multiplex circuit section are formed on the same substrate. 3. The television tuner unit according to claim 1, wherein the tuner section, the intermediate frequency circuit section, and the audio multiplexing circuit section are formed on separate substrates, respectively, and the intermediate frequency section is formed. Connection between the circuit unit and the audio multiplex circuit unit, and
A television tuner unit in which the tuner section and the intermediate frequency circuit section are directly connected by a connector. 4. The television tuner unit according to claim 1, wherein a terminal associated with the audio multiplex circuit section is provided.