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The `complex sound generator` recently intro-duced by Texas Instruments is intended for generating sound effects. This 28-pin IC, the SN76477N, is one of the first linear 12L chips. A wide range of applications is suggested by TI: alarm indicators, timers, sound effects in toys, TV-games, etc. The internal block diagram of the SN76477N is shown in figure 2, together with some external components. The `complex sound` produced by the chip is determined by two analogue voltages (pitch and external VCO control), eight logic levels and a handful of fixed resistors and capacitors. Three basic sig-nals are generated by a `Super Low Frequency Oscillator` (SLF), a Voltage Controlled Oscil-lator (VCO) and a noise generator.