The internal circuit principle of uPC1892

cPC1892 is a four-channel surround sound processing circuit launched by Japan's NEC company after the three-channel
surround sound processing circuit lrPC1891. This circuit adopts a matrix phase-shifting surround sound processing system, which can separate a two-channel or monophonic sound source signal
into two pre-main amplifier signals and two rear surround-sound signals. It also has
three sound field modes: concert hall, cinema and simulated stereo, which can produce an immersive four-dimensional surround sound effect. The circuit is equipped with surround sound effect control and
tone control, and the surround sound effect and volume can be adjusted at will. , balance, high and low. The control of each part adopts DC control
, so that the noise of the entire circuit is extremely small.
    plPC1892 is a large-scale integrated circuit, and its internal circuit principle is shown in Figure 5-23. As can be seen from the figure, its
interior consists of amplifier, low-pass filter, mode control , phase shifter, effects processor, compensation absorption, volume, tone,
balance and other circuits. The circuit adopts dual in-line 30-pin package.