Dolby IC CX1100 series and applications

It is the internal circuit principle and application of CXA1100 series IC. In the picture, SAt is the Dolby switch, and SAz is the record/
playback switch. When SA2 is placed in the recording (R) position, the recording signal enters the A amplifier through the l (16) pin for amplification.
The amplified signal is sent to the main channel adder , the variable attenuation circuit of the auxiliary channel and the B amplifier respectively. Part of the signal output by the B amplifier
enters the adder through the high-pass filter and is added to the main channel signal, so that the high-frequency small signal is improved;
the other part is amplified by the C amplifier and rectified and filtered by the rectifier filter, and then to the variable The attenuator circuit provides the DC control
voltage. One of the signals output from the adder is sent to the recording head as a recording signal through pin 8 (9); the other
is sent to the A amplifier through the feedback circuit to subtract the input signal , so that high-frequency noise is suppressed.