Dolby noise reducer (CB21105E)

This circuit was found in a National Semiconductor Handbook from the 1990s. The integrated circuit used is from the time and the circuit is stereo.

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Timer 4001 2 (CB16316E)
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High impedance window comparator (CB6091E)
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0 to 9 V x 200 mA power supply (CB18936E)
This simple adjustable source uses a PNP transistor that can be the BD136 for even slightly higher...