JPH0110010Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an audio device for a television receiver, and in particular makes it easier to hear low-quality broadcast signals and reproduces high-quality broadcast signals with high sound quality. It was designed so that it could be obtained.

In general, audio signals from television broadcasts are often inferior in sound quality compared to audio signals from FM radio broadcasts, records, etc. For this reason, in the audio circuits of conventional television receivers, circuits such as high-cut and low-stitch circuits are provided to match this low-quality audio signal to make the audio easier to hear. However, recently, television broadcasts of high quality audio signals such as television audio multiplex broadcasts and live broadcasts have become available. Therefore, it is possible to improve the fidelity of the audio circuit of the television receiver, but when the audio circuit of the television receiver is increased in fidelity, high-fidelity audio signals are played back with high fidelity. However, the problem is that the poor sound quality is emphasized for low-quality audio signals that are inferior in sound quality, making it even harder to hear.

In view of this, the present invention is designed to make low-quality broadcast signals easier to hear and to reproduce high-quality broadcast signals with high quality.

An embodiment of the audio device for the television receiver of the present invention will be described below with reference to FIG.
In FIG. 1, a television audio multiplex program can be listened to.

In FIG. 1, 1L and 1R indicate the left signal and right signal input terminals to which the left output signal and right output signal, respectively, of the audio demodulation circuit of the television receiver are supplied; The left signal and right signal supplied to the input terminals 1L and 1R are respectively supplied to the tone adjustment amplifier circuit 2, and the left signal and right signal obtained at the left signal and right signal output terminals of the tone adjustment amplifier circuit 2 are A left signal output terminal 3L and a right signal output terminal 3R that supply audio signals to the left and right speakers of the television receiver, respectively.
supply to the public.

This tone adjustment amplifier circuit 2 operates as shown by arrow B in FIG.
Maximum emphasis curve for audio signals with frequencies below 1kHz
It is possible to vary between B _MAX and the minimum emphasis curve B _MIN , and further, depending on the magnitude of the DC current as a control signal supplied to the treble control signal input terminal 2T, as shown by arrow T in Fig. 2. It is designed so that the audio signal with a frequency of 1 kHz or more can be varied between the maximum emphasis curve T _MAX and the minimum emphasis curve T _MIN . 4 is the power supply terminal + to which positive DC voltage is supplied
A variable resistor for bus adjustment is connected between B and the ground, and the movable element 4a of the variable resistor 4 for bus adjustment is connected to an npn type transistor 6 that constitutes a bus control circuit via a resistor 5. The base of this transistor 6 is grounded through a series circuit of a diode 7 and a resistor 8, the emitter of this transistor 6 is grounded through a resistor 9, and the collector of this transistor 6 is connected to a tone. Connect to the bus control signal input terminal 2B of the adjustment amplifier circuit 2. In this case, by adjusting the movable element 4a of the variable resistor 4 for bass adjustment, the low frequency side of the audio can be adjusted. Further, 10 indicates a variable resistor for treble adjustment inserted between the power supply terminal +B to which a positive DC voltage is supplied and the ground. The base of this transistor 12 is grounded through a series circuit of a diode 13 and a resistor 14, and the emitter of this transistor 12 is connected through a resistor 15. The collector of the transistor 12 is connected to the treble control signal input terminal 2T of the tone adjustment amplifier circuit 2. In this case, by adjusting the movable element 10a of the variable resistor 10 for treble adjustment, the high frequency side of the sound can be adjusted. In this tone adjustment amplifier circuit 2, the left signal and right signal supplied to the left signal and right signal input terminals 1L and 1R, respectively, are controlled in the same way.

Further, 16 indicates a music control circuit for providing a new function, and this music control circuit 1
6 is two npn type transistors 16a and 16b
The bases of the transistors 16a and 16b are connected to each other, and the connection point of the bases of the transistors 16a and 16b is connected to a power supply terminal +B to which a positive DC voltage is supplied via a bias setting resistor 16c. is grounded through a series circuit of diodes 16d, 16e and a resistor 16f, and the transistor 16
The collectors of transistors 16a and 16b are connected to the power supply terminal +B, and the emitters of transistors 16a and 16b are connected to the bases of transistors 6 and 12 through resistors 16g and 16h, respectively, which constitute a constant current circuit. Connecting. transistor 1
The connecting points of the respective bases of 6a and 16b are connected to one fixed contact 17N of a changeover switch 17 that switches between operation and non-operation of this music control circuit 16, and the other fixed contact 17N of this changeover switch 17
7M is placed in an electrically floating state, and the movable contact 17a of this changeover switch 17 is grounded. In this case, when the movable contact 17a of the changeover switch 17 is connected to one fixed contact 17N, the bases of the transistors 16a and 16b are grounded, so the music control circuit 16 becomes inoperable, and the movable contact 17a is connected to the other fixed contact 17N. When connected to contact 17M, music control circuit 16 is in operation. In this case, when the music control circuit 16 is in operation, a predetermined constant current is supplied to the transistors 6 and 12 via the transistors 16a and 16b, respectively. They are respectively supplied to input terminals 2T. At this time transistor 1
The constant current flowing through 6a and 16b is the tone adjustment amplifier circuit 2 when the movable element 4a of the variable resistor 4 for bass adjustment and the movable element 10a of the variable resistor 10 for treble adjustment are respectively at the center position.
For example, as shown in Figure 3B, the frequency characteristics of 140 Hz are boosted by 6 dB for audio signals with frequencies below 1 kHz based on 1 kHz, and the audio signals with frequencies above 1 kHz are boosted by 6 dB. The characteristics should be such that the frequency is boosted by 3dB at 7kHz. Also in this case, the music control circuit 16
When the tone adjustment amplifier circuit 2 is not in operation, the frequency characteristics of the tone adjustment amplifier circuit 2 are such that no tone quality adjustment is performed, as shown in FIG. 3A.

Since the present invention is constructed as described above, when receiving a television broadcast signal such as news with poor sound quality, the mover 17a of the changeover switch 17 is turned off.
is connected to one fixed contact 17N, and the music control circuit 16 is rendered inoperable. At this time, for example, high cut and low boost are used as in the conventional case, and the sound is easy to hear without emphasizing poor sound quality. Also, when receiving high-quality television broadcast signals such as music programs of audio multiplex programs, move the movable element 17a of the changeover switch 17 to the other fixed contact 17M.
If the music control circuit 16 is activated, the frequency characteristics of the tone adjustment amplifier circuit 2 will be such that they can be reproduced with high fidelity as shown in FIG. 3B. It can be played back with high fidelity and provides high quality audio. In this case, according to the present invention, it is possible to switch between high fidelity playback and normal playback with the changeover switch 17, so the variable resistor 4 for bass adjustment can be adjusted each time depending on the program.
movable element 4a and variable resistor 1 for treble adjustment
There is an advantage that there is no troublesome adjustment of the movable element 10a of 0 to the optimum point.

Also, in Fig. 1, variable resistor 4 for bus adjustment is shown.
By adjusting the movable element 4a of the tone adjustment amplifier circuit 2, the bass can be adjusted, and by adjusting the movable element 10a of the variable resistor 10 for treble adjustment, the tone adjustment amplifier circuit 2 can be adjusted. It goes without saying that the high frequency characteristics of the amplifier circuit 2 can be adjusted and the treble can be adjusted.

As described above, according to the present invention, there is an advantage that the audio signal can be made easier to hear when compared to a low-quality broadcast signal, and the audio signal can be reproduced with high quality when compared to a high-quality broadcast signal. Furthermore, according to the present invention, the changeover switch 17 is used to switch between high-fidelity playback and normal playback, so there is an advantage that there is no need to make bass adjustment and treble adjustment each time depending on the program.

It goes without saying that the present invention is not limited to the above-described embodiments, and that various other configurations may be adopted without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the audio device of the television receiver of the present invention, and FIGS. 2 and 3 are diagrams for explaining the present invention, respectively. 1L and 1R are audio signal input terminals, 2 is a tone adjustment amplifier circuit, 3L and 3R are audio signal output terminals,
4 is a variable resistor for bass adjustment, 6 is a transistor forming a bass control circuit, 10 is a variable resistor for treble adjustment, 12 is a transistor forming a treble control circuit, 16 is a music control circuit, and 17 is a changeover switch. .

Claims (1)

[Claims for Utility Model Registration] A first active element connected to a bass control control terminal of a tone adjustment amplifier circuit, and a bass adjustment variable resistor connected to the control terminal of the active element. , a bass control circuit that controls the low frequency characteristics of the tone adjustment amplifier circuit, and a second active element connected to the treble control control terminal of the tone adjustment amplifier circuit;
a treble control circuit configured with a treble adjustment variable resistor connected to a control terminal of the active element and controlling the high frequency characteristics of the tone adjustment amplifier circuit; and a treble control circuit that controls the high frequency characteristics of the tone adjustment amplifier circuit; In order to control the operation, it has a control circuit that gives a control signal to the first and second active elements, and a switching means that can arbitrarily switch the state of the control circuit, and the switching means The control circuit is provided independently from the switch, and has first and second states, and in the first state, the control circuit operates the bass control circuit and the treble control circuit by the switching means. A control signal is applied to the control terminals of the first and second active elements to adjust the frequency characteristics according to the low and high frequency characteristics preset by the respective adjustment variable resistors. The tone adjustment amplifier circuit is always controlled, and in the second state, the switching means sends a control signal to the first and second amplifier circuits to disable the bass control circuit and the treble control circuit. 1. An audio device for a television receiver, characterized in that the audio device is applied to a control terminal of an active element, and is controlled so as not to be influenced by the adjustment state set in advance by each of the adjustment variable resistors.