decoding is done in the DEMDEC block of the Sound DSP. The DEMDEC processing will be described in the next chapter.
The audio signals (AUD ADC IN) from the analogue crossbar pass the audio ADC and are fed directly into the AUDIO part of the Sound DSP like the I2S signals, which is coming from I2S processing hardware. After level adjust all signals from the DEMDEC and the I2S input are available at the digital input crossbar. A special input is provided for the Noise/Silence Generator needed for olby® Pro Logic® processing.
In standard TV applications the main channel signal(L,R) will be connected to the DAC2 for reproduction at the speakers. With multichannel signals centre, surround or subwoofer channels may be passed to the I2S outputs where external DACs may be applied. By this it is possible to build Dolby Normal/Wide, Dolby Phantom Centre or Dolby 3 Stereo
5.4.3 Demodulator and decoder
INTRODUCTION
The TV sound processor provides an
The sound demodulator is able to search for sound carriers and react to transmission mode changes autonomously, without interaction of the micro controller software.
It is possible for a typical terrestrial TV application to setup the entire demodulator with transmission of few control words.
The control interface still allows access to every detail, called demodulator expert mode, for special applications such as satellite TV, more elaborated search algorithms etc.
The new TV Sound ProcessorDemodulator and DecoderEasyProgramming(DDEP)interfaceprovides three possible approaches to setup the demodulator and decoder parts:
nAuto Standard Detection (ASD)
nStatic Standard Selection (SSS)
nDemodulator and Decoder Expert Mode (DDXM)
MIXER
The digitized 2nd SIF input signal is fed to the mixers, which mix one or both input sound carriers down to zero IF. The mixer frequency is derived by the standard setting (Easy Programming) or in the Demodulator and Decoder Expert Mode (DDXM) by a
FMANDAMDEMODULATION
An FM or AM input signal is fed via a
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