公开(公告)号：CA1179949A

公开(公告)日：1984-12-27

申请号：CA401115

申请日：1982-04-16

Applicant: RCA CORP

Inventor： GRIFFIS PATRICK D

IPC: H03G3/02 ,  H03G3/04 ,  H03G3/10 ,  H04S7/00 ,  H04R5/04

Abstract: -14- RCA 76,585 First and second sound channels are provided for processing audio signals. Each sound channel includes means responsive to a D.C. control voltage for controlling the volume of the audio output signal of the channel. A volume control potentiometer is coupled across two terminals of a source of supply voltage and a D.C. volume control potential is developed at a tap of the potentiometer. The volume control potential is applied to a control electrode of a controlled current path. The controlled current path includes the parallel combination of a first voltage divider and a second, variable voltage divider. A tap of the first voltage divider is coupled to the D.C. control input of the first sound channel, and a tap of the second voltage divider is coupled to the D.C. control input of the second sound channel. By adjusting the second, variable voltage divider, the control voltage provided by the second voltage divider may be set to equalize the D.C. volume control characteristics of the two sound channels.

公开(公告)号：CA1135839A

公开(公告)日：1982-11-16

申请号：CA346611

申请日：1980-02-28

Applicant: RCA CORP

Inventor： GRIFFIS PATRICK D

IPC: H04S5/00 ,  H04N9/60

Abstract: - 34 - RCA 73,587 A system is provided which synthesizes stereophonic sound by developing two separate sound channels from a single monophonic sound source. A synthetic stereophonic sound system constructed in accordance with the principles of this invention may be advantageously utilized in combination with a visual display such as a television receiver. A monaural signal (M) is applied as the input signal for a transfer function circuit of the form H(s), which modulates the intensity of the monaural signal as a function of frequency. The intensity modulated H(s) signal is coupled to a reproducing loudspeaker, and comprises one channel (B) of the synthetic stereo system. The H(s) signal is also coupled to one input of a differential amplifier (40). The monaural signal (M) is coupled to the other input of the differential amplifier (40) to produce a difference signal (M-H(s)) which is the complement of the H(s) signal. The difference signal is coupled to a second reproducing loudspeaker, which comprises the second channel (C) of the synthetic stereo system. In accordance with a preferred embodiment of the present invention, a stereo synthesizer is utilized as the sound reproducing system of a television receiver, with the reproducing loudspeakers located on either side of the kinescope. The amplitude -vs- frequency response curves of the two output channels (B,C) have crossover points at which the amplitudes of the two response curves are equal, which effectively centers sounds at these frequencies between the loudspeakers. Two crossover frequencies are chosen to occur at approximately the frequency of peak intensity of the human voice, and at the center frequency of the second (articulation) formant frequencies of the human voice so as to effectively center voices on the kinescope while preserving the ambience effect of other, more randomly distributed sound signals. Centering the second formant frequencies also provides increased quality in the reproduction of speech sounds.

公开(公告)号：CA1212465A

公开(公告)日：1986-10-07

申请号：CA439437

申请日：1983-10-21

Applicant: RCA CORP

Inventor： GRIFFIS PATRICK D ,  RINDAL ABRAHAM E

IPC: H03D3/02 ,  H04N5/60 ,  H04N5/62

Abstract: A frequency translation phase locked loop (PLL) is provided for detecting the audio information from a received television signal. The PLL includes a switching arrangement which, in a first position causes the loop to process the IF picture and sound carriers for detecting the audio information in an intercarrier type of detection method and, in a second position causes the loop to process the IF sound carrier for detecting the audio information without the use of the received picture carrier, in a "separate" (split-sound) type of audio detection method.

公开(公告)号：CA1178897A

公开(公告)日：1984-12-04

申请号：CA401104

申请日：1982-04-16

Applicant: RCA CORP

Inventor： GRIFFIS PATRICK D

IPC: H04S1/00 ,  H04S5/00

Abstract: - 19 - RCA 77,078 A system for synthesizing stereophonic signals from an audio information signal source is provided. The system includes a transfer function circuit for producing a modulated signal which varies in amplitude as a function of frequency in response to the audio signal, first and second amplifiers for providing amplified output signals, and a switch circuit for coupling selected ones of the audio signal and the modulated signal to the inputs of the first and second amplifiers. In a first position, the switch circuit causes the first and second amplifiers to operate in a matrix mode for matrixing the input signals to provide first and second synthesized stereophonic output signals, and in a second position, the switch circuit causes the amplifiers to operate in a non-matrix mode with respect to the input signals supplied thereto for providing an amplified audio output signal.