This part is a kind of semiconductor called BL3207B.

Function of this product has 1024-stage low voltage operation and low noise BBD variable delay line.

Manufacturers : SHANGHAI BELLING

Image and pinout :

Some of the text within the PDF file :

BL3207A/B 1024-Stage BBD Description The BL3207A/B is a 1024-stage low voltage operation,and low noise BBD variable delay line in audio frequency range. The device operates on +5V to +10V supply and provides a signal delay up to 51.2ms. Pin Assignment GND CP1 IN VGG PDIP 8 PIN BL3207 OUT 2 OUT 1 CP 2 VDD Features ¡¤ Adjustable audio signal delay time range:2.56ms-51.2ms ¡¤ Wide supply voltage range:4V-10V ¡¤ Typical insertion loss: Li=0dB ¡¤ Wide dynamic range: S/N=73dB(type) ¡¤ Low distortion: THD=0.4%(type) ¡¤ Clock frequency range:10kHz-200kHz ¡¤ N-channel silicon gate process ¡¤ 8-pin plastic DIP Application KARAOKE, TV, VCR. Radio-Cassette Tape Recorder etc. Application Circuit Vdd IN 100K 100K 100K Low Pass Filter f140dB/oct [ ... ]

BL3207B PDF Datasheet Download