Electrical audio signal processing systems and devices – Including frequency control
Patent
1981-08-24
1984-02-14
Pellinen, A. D.
Electrical audio signal processing systems and devices
Including frequency control
H03G 514
Patent
active
044320973
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a tone control circuit, which is provided with a filter circuit supplied with an audio signal, a gain control circuit supplied with the output from the filter circuit and an operational circuit adding the input audio signal and the output from the gain control circuit with each other to carry out tone control due to the characteristic of the filter circuit and the gain of the gain control circuit and to primarily control the gain with a DC voltage which is suitable for remote control.
BACKGROUND ART
At present, the television broadcast of a voice-multiple system is practised and the quality of voice or sound in the television broadcast is remarkably improved. In association therewith, it is required that the sound field thereof are be improved. Further, in view of remote control operation of a television receiver, it is also desired that the tone control can be remotely controlled with a DC voltage. Moreover, when the circuitry of the television receiver is made as an integrated circuit, be it is necessary that the tone control circuit constructed as an integrated circuit.
In consideration of the above points, the inventors have already proposed a tone control circuit which is different from the prior art attenuation type CR system and the feedback NF system.
FIG. 1 shows the above proposed tone control circuit in which an input signal from an input terminal 10 is supplied to an adder 20. The input signal from the input terminal 10 is also fed to a boost signal line consisting of a filter 31, an amplifier 32 and a gain control circuit 33 and the output signal therefrom is fed to an add input of the adder 20. The input signal from the input terminal 10 is supplied further to a cut signal line consisting of a filter 41, an amplifier 42 and a gain control circuit 43 and the output signal therefrom is supplied to a subtract input of the adder 20. At the adder 20, the signal transmitted through the boost signal line is added to the input signal and the signal transmitted through the cut signal line is subtracted from the input signal. Thus, an output signal is derived from the adder 20 and is supplied to an output terminal 60. A voltage V.sub.C derived from a volume control 50 is applied to the gain control circuits 33 and 43 as the gain control signals.
With the above circuit, if the filters 31 and 41 are each made or used as a high pass filter, the boost and cut in a high frequency band are obtained, while if the filters 31 and 41 are each made as a low pass filter, the boost and cut in a low frequency band are obtained.
That is, when the control voltage V.sub.C is in the range from a center value V.sub.O to zero, the gain control circuit 33 is set such that its gain is zero. On the contrary, the gain control circuit 43 is so set that when the control voltage V.sub.C is in the range from the center value V.sub.O to the maximum value 2V.sub.O, its gain becomes zero. Accordingly, when the control voltage V.sub.C is at the center value V.sub.O, the output signals from the gain control circuits 33 and 43 are both zero. Thus, at the output terminal 60 the input signal unchanged will be obtained unchanged and, the frequency characteristic at this time will be flat.
When the control voltage V.sub.C is changed from the center value V.sub.O to the maximum value 2V.sub.O, it is set so that the gain of the gain control circuit 33 increases and becomes 1 at the maximum value 2V.sub.O. Accordingly, at this state, if the gain of the amplifier 32 is taken as A.sub.1, as shown in FIG. 2 the gain of the boost signal line becomes A.sub.1. Therefore, the boost becomes a high boost of A.sub.1 +1 where of course A.sub.1 >0.
On the contrary, when the control voltage V.sub.C is changed from the center value V.sub.O to zero, it is set so that the gain of the gain control circuit 43 increases and becomes 1 at zero. Accordingly, at this state, if the gain of the amplifier 42 is taken as A.sub.2, as shown in FIG. 3 the gain of the cut signal line becomes A.sub.2. Therefore, the cut becom
REFERENCES:
patent: 3646270 (1972-02-01), Shiga et al.
patent: 3908172 (1975-09-01), Aschermann et al.
patent: 4055818 (1977-10-01), Gay
patent: 4223181 (1980-09-01), Simeau
patent: 4289928 (1981-09-01), Takaoka et al.
patent: 4290335 (1981-09-01), Sondermeyer
patent: 4320534 (1982-03-01), Sakai et al.
patent: 4347404 (1982-08-01), Kawasaki
Nakajima Hajime
Okada Takashi
George Keith E.
Pellinen A. D.
Sony Corporation
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