HT8955A
Voice Echo
Features
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Operating voltage: 5.0V
Long delay time
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0.8 seconds (SEL=VSS, 256K DRAM)
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0.2 seconds (SEL=VDD/open, 64K DRAM)
25kHz sampling rate
Continuous variable delay time
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Built-in pre-amplifier
Low distortion
High S/N ratio
Wide frequency response
PCM 10-bit A/D and D/A converters
24-pin DIP package
Applications
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Mixers
Karaoke systems
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Echo generators
Sound effect generators
General Description
The HT8955A is a CMOS LSI digital audio
signal delay processor. It is designed for
audio system applications including echo
generators, karaoke systems, sound effect
generators, etc.
The chip consists of a built-in pre-amplifier,
on-chip oscillator, DRAM interface, 10-bit A/D
and D/A converters as well as control logic. It
provides continuously adjustable delay time up
to 0.8/0.2 seconds at a sampling rate of 25kHz
when combined with an external DRAM
(41256/4164). The HT8955A is superior to a
conventional BBD delay unit in its low distor-
tion, high S/N ratio and long delay time. Its
sophisticated low pass filter will not end in the
normal applications due to the high sampling
rate (25~50kHz). Hence, the HT8955A is excel-
lent for audio delay system applications. It is
offered in a 24-pin dual-in-line package.
Pin Assignment
Block Diagram
1
5th May ’98
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
