JPS6121005B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switching and composite signal output device used in a television receiver capable of receiving audio multiplex television broadcasts, an audio multiplex reception adapter device used with this receiver, and the like.

In audio multiplex television broadcasting, the audio signal of a sub channel is superimposed on the audio signal of a main channel and then broadcast, allowing the receiving side to listen to stereo audio or audio from different programs simultaneously or selectively. This broadcast is generally
FM modulated by the main channel audio signal
It uses the FM-FM method, in which the 4.5MHz audio intermediate frequency is FM-modulated by the audio signal of the sub-channel, and then FM-modulated again by the 31.5KHz sub-carrier.
In order to receive the above broadcast on the receiving side,
A broadcast type discrimination circuit for distinguishing the type of broadcast (monaural broadcast, different program broadcast, stereo broadcast), and a signal switching and synthesis device for processing and outputting audio signal information according to the discrimination output of this half-divided circuit. is necessary. The type of broadcasting is determined by AM detection of control signals multiplexed and sent from the broadcasting side.In the case of different program broadcasting, a 922.5Hz pilot signal is used, and in the case of stereo broadcasting, a 922.5Hz pilot signal is used. A 982.5Hz pilot signal is obtained, which is passed through a filter circuit and used as discrimination information. Note that monaural broadcasting is when there is no pilot signal.

Next, in the signal switching and combining device,
A main channel signal is introduced into the first input terminal, and a sub-channel signal is introduced into the second input terminal. Therefore, depending on the type of broadcasting, it is necessary to combine the signals of each channel and output them to the output end, or to select and output only one of them. For example, in the case of a different program broadcast, the main channel contains Japanese sound and the sub channel contains foreign language sound, so that the user can switch between them according to his/her preference. Further, in the case of stereo broadcasting, since the main channel contains an L+R signal and the sub channel contains an LR signal, it is necessary to derive each of the L and R signals to the output end through a matrix circuit. In particular, in the case of stereo broadcasting, the signal at the input end is not simply led out to the output end as is the case with different program broadcasts, but it must be led out through a matrix circuit, so it is difficult to obtain good stereo separation. It is necessary to be

This invention was made in order to cope with the above-mentioned situation, and even if the signals applied to the input terminal are different types of signals (for example, Japanese and foreign languages),
Even if it is a signal, the output end can derive the desired output according to the input signal, has a wide range of switching functions, and can also form a high-performance matrix circuit with a simple configuration. The object of the present invention is to provide a signal output device.

Embodiments of the present invention will be described below with reference to the drawings. That is, FIG. 1 shows a circuit in which the basic operation is extracted in order to facilitate understanding of the present invention, and transistors T ₁ and T ₂ have transistors T 3 and T ₃ connected to their respective emitters (controlled electrodes). The collector of _T4 is connected and each transistor
Input terminals ₁ , ₂ , ₃ , _{and 4} are set at the bases (control electrodes) of T 1 , T 2 , T 3 , and T 4 . The emitters of the transistors T ₃ and T ₄ are connected to resistors R ₁ and R ₂ respectively.
The collectors of the transistors T ₁ and T ₂ are connected via resistors R ₃ and R ₄ (the resistors may be variable resistors), respectively.
It is connected to a DC reference voltage source E. An output terminal 5 is connected to the collectors of the transistors T ₁ and T ₂ .
6 is set. Also, the transistor
A resistor _R5 is connected between the emitters of _T1 and _T2 .

In the above configuration, if the resistors R ₁ and R ₂ are equal, the resistors R ₃ and R ₄ are also equal, and the ratio of the resistors R ₁ , R ₃ , and R ₅ is set appropriately, an AC signal can be output from terminals 1 and 2. When supplied with an input, this circuit operates as a differential amplifier. Output signals having mutually opposite phases and equal amplitude can be obtained between the output terminal 5 and the ground and between the output terminal 6 and the ground. Furthermore, input terminal 3 (or 4)
If a signal is added to the amplifier, it operates as a cascode amplifier, and an output signal can be obtained only at the output terminal 5 (or 6). Now, select the resistors R ₁ to _{R 5} appropriately to obtain a voltage gain of 2A as a cascode amplifier.
If the voltage gain as a differential amplifier is also 2A times (differential output between output terminals 5 and 6), the voltage gain between output terminal 5 or 6 and ground (unilateral output voltage gain)
becomes A times.

Here, assuming the case of stereo broadcasting among audio multiplex television broadcasts, the audio signals of the main and sub channels are (L+R) and (L-
It becomes a component of R). When the L+R signal is supplied to input terminals 1 and 4, and the L-R signal is supplied to input terminal 2, output terminal 5
The output (between ground) is -A{(L+R)-(L-R)}=-2AR The output of output terminal 6 (between ground) is -A{(L+R)-(L-R)}- 2A(L+R)=
-2AL, and each component of the stereo matrixed right signal R and left signal L is obtained.

Stereo separation in this circuit itself is
For example, resistance R ₁ = resistance R ₂ = 0.5kΩ to 2kΩ, resistance R ₃
= Resistance R ₄ = 0.5kΩ to 2kΩ, Resistance R ₅ = 0.5kΩ to 2k
If you choose around Ω, you can get more than 30dB to 40dB.

In addition, when receiving different program multiplex broadcasts, the main and sub channel audio signals are M and M, respectively.
S, either one of M or S is supplied to input terminals 3 and 4, or input terminals 3,
4 may be supplied with M or S. However, in this case, the output level will be -2AM or -2AS, which is double that of stereo, so please set the M/
It is preferable to adjust the level to 2, S/2 and supply it.
Note that when the above circuit configuration is operated as a differential amplifier, a signal is supplied to the bases of the first and second transistors, and the same or different constant voltage power supplies are supplied to the bases of the third and fourth transistors. A switching means is required for supplying the voltage, which can be realized by various switching devices using switching transistors. The same applies when operating as a cascode amplifier, in which the same or different constant voltage power supplies are supplied to the bases of the first and second transistors, and a signal is supplied to both or one of the bases of the third and fourth transistors. be done.

By operating as described above, it is possible to switch and use it as a matrix circuit, differential amplifier circuit, cascode amplifier circuit, etc. with a simple configuration.
You can get a wide variety of functions depending on your application.

A specific embodiment based on the above circuit and having a function switching section will be described with reference to FIG. Components having the same functions as those in FIG. 1 are given the same reference numerals. That is, a transistor _T5 having a common emitter and a collector connected to the DC reference voltage source E is connected to the transistor _T1 . Also, for the transistor _T2 ,
A transistor _T6 having a common emitter and a collector connected to the DC reference voltage source E is connected. The bases of the transistors T ₅ and T ₆ are commonly connected. Next, the output ends 5 and 6
The collectors of transistors T ₇ and T ₈ are connected to. The bases of the transistors T ₇ and T ₈ are commonly connected, and their emitters are commonly connected to the collector of the transistor T ₉ .
The emitter of this transistor _T9 is grounded to the reference potential terminal via a resistor _R6 having a value equal to the resistors _R1 and _R2 .

On the other hand, transistors T ₁₀ and T ₁₁ are transistors for switching operational functions. The emitter of the transistor _T10 is grounded to the reference potential terminal,
The collector is connected to the transistor through a resistor _R15 .
Connected to the base of _T9 . Further, the emitter of the transistor _T11 is also grounded to the reference potential terminal, and the collector is connected to _the transistor _T5 ,
Connected to the common base of T ₆ . Furthermore, the transistors T ₁₀ and T ₁₁ are controlled by a manual or automatic switching device 8 , the common base of both transistors being connected to a DC voltage source E via a resistor R ₁₉ and connected to the switching device 8. It is connected to the selection side output terminal 9 of 8 . Further, this output terminal 9 is grounded to a reference potential terminal via a resistor _R20 .

Next, transistors T ₁₂ and T ₁₃ are transistors that constitute a bias circuit, and transistors T _{12 and} T 13 are transistors that constitute a bias circuit.
Its collector is connected to the DC voltage source E, and its emitter is connected to the collector of the transistor _T13 . Furthermore, the base of the transistor _T12 is connected to the DC voltage source E through a resistor _R16 , and the base of the transistor T12 is connected to the DC voltage source E through a resistor ₁₇ .
Connected to the base of T ₁₃ . The base of this transistor _T13 is further grounded to the reference potential end via a resistor _R18 , and the emitter is grounded to the reference potential end via a resistor _R21 .

To explain the bias supply path, the emitter of the transistor _T12 is connected to the base of the transistor _T1 via a resistor _R7 , and to the base of the transistor _T2 via a resistor _R8 . Furthermore, the emitter of the transistor T ₁₂ is connected to the resistor R ₉
is connected to the bases of the transistors T ₅ and T ₆ through a resistor R ₁₁ .
Connected to the base of T ₇ and T ₈ .

Next, the emitter of the transistor _T13 is a resistor
It is connected to the base of the transistor T ₃ via R ₁₂ and to the base of the transistor T ₄ via a resistor R ₁₃ . Further, the emitter of the transistor _T13 is connected to the base of the transistor _T9 via a resistor _R14 . In addition, resistance
R ₅ is assumed to be a variable resistance.

In the above connection configuration, during stereo broadcasting, the switch device 8 is automatically or manually switched to the open end 10 side, and the transistors T ₁₀ ,
T ₁₁ is turned on. For this reason, the transistor T ₅ ,
T ₆ , T ₇ , T ₈ , and T ₉ are turned off, and a circuit exactly the same as the circuit shown in FIG. 1 is formed. Here, by adding the L+R signal to input terminals 1 and 4 and the LR signal to input terminal 2, -2AR and -2AL can be obtained at output terminals 5 and 6, respectively.

Further, during monaural broadcasting, the switch device 8 is automatically or manually switched to the reference potential end 11 side, and the transistors T ₁₀ and T ₁₁ are turned off. Therefore, transistors T ₁ , T ₂ , transistors T ₅ ,
T ₆ , transistors T ₇ , T ₈ , etc. each operate as a differential amplifier, and transistor T ₉ operates as a common emitter type amplifier. Here, terminal 3 or 4
If a monaural audio signal is applied to (or both), a monaural signal is obtained at the output end 5 or 6 (or both). (The gain is multiplied by A) When broadcasting a different program, either the -AM or -AS signal can be obtained at the output terminals 5 and 6 by similarly selecting the signals at the input terminals 3 and 4. During this _{operation ,} compared to _the circuit shown _{in FIG} . ₆ so that there is no change in the DC output level
Compensation for the DC current flowing through T ₅ and T ₆ can be obtained.

As a result, according to the device of this invention, monaural,
The AC gain is constant regardless of the broadcast contents of stereo or different programs, and there is no output DC level fluctuation due to signal switching.
Furthermore, by using the resistor _R5 as a variable resistor, it is possible to adjust the degree of stereo separation in stereo mode. In this case, the degree of separation can be improved by connecting the slider of resistor _R5 to a suitable reference potential point via a suitable capacitor. Furthermore, the device of the present invention has a simple structure and is clearly suitable for integration into an integrated circuit. Note that this invention is not limited to the above embodiments,
It can also be constructed using not only NPN transistors but also PNP transistors. Furthermore, its uses are wide-ranging, not just as an audio multiplex broadcast switching and synthesizing device.

As explained above, according to the present invention, the operational functions can be easily switched for various input signals, and the circuit can have the functions of a differential amplifier, stereo matrix circuit, cascode amplifier, etc., and its structure is It is possible to provide a switching and composite signal output device that is simple and suitable for integration into an integrated circuit.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a basic embodiment of the invention, and FIG. 2 is a circuit diagram showing an embodiment to which the invention is applied. _T1 , _T13 ...Transistor, _R1 , _R20 ...Resistor, 1, 2, 3, 4...Input terminal, 5, 6...Output terminal, 8 ...Switch device.

Claims (1)

[Claims] 1 First and second input terminals are set for each control electrode, and each controlled electrode is connected to a first reference potential point via a first and second load, respectively, and is also connected to an output terminal. a third load connected between the controlled electrodes of the other of the first and second semiconductor active elements, and the first and second semiconductor active elements; third and fourth semiconductor active elements in which one controlled electrode is controlled by each other controlled electrode, and third and fourth input terminals are set in each control electrode; A resistor is connected between each other controlled electrode of the fourth semiconductor active element and the second reference potential point, and a resistor is provided corresponding to the first semiconductor active element, and one controlled electrode is connected to the second reference potential point. a fifth semiconductor active element connected to the first reference potential and whose other controlled electrode is connected to the other controlled electrode of the first semiconductor active element; Control electrodes are connected and provided corresponding to the second semiconductor active element, one controlled electrode is connected to the first reference potential point and the other controlled electrode is connected to the second semiconductor active element.
A sixth semiconductor active element is connected to the other controlled electrode of the semiconductor active element, and one controlled electrode is connected to each of the first and second output terminals, and their control electrodes are commonly connected. The seventh and eighth semiconductor active elements and the other controlled electrodes of the seventh and eighth semiconductor active elements are commonly connected to one controlled electrode, and the other controlled electrode is connected to the second controlled electrode through a resistor. a ninth semiconductor active element connected to a reference potential point; a bias circuit that supplies a bias to the control electrodes of the first to ninth semiconductor active elements; and the fifth and sixth semiconductor active elements and the ninth semiconductor active element. 1. A switching and composite signal output device comprising: a semiconductor control element for controlling the control electrode potential of a semiconductor active element according to a switching signal from a switching device.