The BA1701 is a monolithic audio-compression system controller IC that uses VSC∗.
When used in combination with an analog delay circuit and low-pass filter, it can replay recorded audio at 1 to 2.5 times
the recording speed, without altering the pitch.

Features
1) Wide operating voltage range (4.5V to 14V).
2) Built-in two-phase sweep oscillator that can directly drive BBD.
3) Built-in motor controller is synchronized with the audio compression ratio.
4) Built-in voltage regulator.

Applications
    Audio compression systems for tape-based answering machines and learning aids