In the movie and music mode the signal difference from the left and right stereo channels will directly reach at the input of the first internal-chip phase shift. The internal signal switch controlled through modecontrol is found in the bottom switch position.
While in music mode the audio signal is already gathered after the only phase shifting PS1, the signal in Movie mode is passed through all the 4 phase sliders. Even with a simple mono-signal the (IC 1) can generate a bewildering good room sound.
At first an addi- tion of the two identical signals of the left and right stereochannels is obtained in the simulated mode. After passing of a high-pass externally connected on pin 28 and pin 29 and a low—pass connected with a condenser on pin 27 the forma- tion of a signal difference is obtained. This signal difference passes then again all the 4 phase shifts in the simulated mode.
The phase shifts are externally connected at a given time only with a few condensers on pin 2 to pin 5. The effective low is directly variable in all operating modes with the help of a adjusting regulator (Surround). After passing of another low—pass filter with an external condenser on pin 30 and a stage
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Now let us go back to the main diagram in fig.1. The semi-operating voltage buff- ered with C14 is gathered on pin 24 of the chip. The audio output signals from the chip reach directly at the RCA socket-output SK3 to SK6 through the electrolytic condenser C26 to C29.
An unstabllised DC voltage in the range between 14V and 18V with at least 150mA current is essential for the voltage supply of SSP-2001 — Surround-Sound—Decoder.
At first the voltage reaches at the buffer electrolytic condenser C1 as well as at the two inputs of the fixed voltage regulator lC3 and IC4 through the mechanical switch S2 .
While lC3 delivers at first a stabilized 5V for the trimming potentiometer, IC4 is responsible for the stabilization of the operating voltage at 12 V. The electrolytic condensers C3O and C3 are used for general stabilization and for the suppression of oscillations. The ceramic condensers C2, C4, C31 and C34 eliminate the frequently occurring noise interference.