SCSS014A - MARCH 1994 - REVISED JANUARY 1996
The Texas Instruments (TITM) TMS320AV120 is a low-cost, stand-alone MPEG audio decoder. It implements the ISO-MPEG audio decompression algorithm for layers 1 and 2. MPEG-compliant audio data streams at any of the valid MPEG data and sampling rates are accepted, producing decompressed PCM audio output. Mono, dual, stereo, and joint-stereo modes are supported. The serial-output data stream is suitable for direct input to most commercially available one-bit D/A converters.
The design intent is to produce a simple, plug-and-play audio decoder that does not require a host microprocessor for initialization and/or operation. The input is in MPEG audio-frame format with provisions for audio/video synchronization. It is a single-chip solution with no provision or need for external buffer memory. The input-data rate should match the actual compressed-audio-bit rate, although the 'AV120 has an input buffer to absorb short-term input bit-rate variations. Ancillary data in the bit stream is recovered and output serially. When the compressed-audio data is at the actual bit rate, a pulse-width-modulated error signal is generated if the PCM output clock is not at the required frequency.
The decoded-sampling rate, stereo mode, error status, and de-emphasis information is available in the serial status register synchronously with the beginning of the associated PCM data frame. The complete MPEG frame header can also be read from the chip.
In systems where audio/video synchronization is required, the TMS320AV120 accepts the system clock reference (SCR) and the audio presentation time stamp (PTS) information and synchronizes the audio output to these time stamps.
View more information about generic part numbers:TMS320AV120
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