I had a few doubts/questions regarding the High Sample Rate Audio Codecs (192k to 768k) Audio Codecs available from Analog Devices. I was trying to use the Audio Codecs for waveform generation and capture at frequencies above 20kHz and below 60kHz. While looking into the many data sheets of high speed audio codecs, which have sample rates of 192kHz and 768kHz, I am finding a reference of a filter that provides a cutoff at 20kHz or nearby (A Weighted Filter and 20kHz Flat Cutoff Filters). I was wondering about the following questions:
1. Is it possible to bypass this filter so that the full sample rate capacity of the codec can be used to sample relatively high frequency voltage waveforms above the human auditory range ? I am particularly interested in this because then it lets me use the I2S interfaces and software layers available with popular DSPs and embedded Operating Systems, without designing an interface for an ADC/DAC and it would help me reduce my circuit foot print, for building ultrasound applications.
2. Are there any audio codecs that is available from Analog Devices that can do 192Ksps or above sample rate at 24 bits without the filters and providing cutoff at or near half Nyquist Rates ?
3. If these filters are not removable from the processing chain, and if these codecs are limited in operation to 20kHz and below, what additional benefit is provided by the high sample rates provided by 192k and 768k codecs ? Does it improve fidelity in some sense ? Isnt 48k or 96k sufficient enough ? What kind of applications actually use these high sample rates in an audio codec with a filter that limits audio pass band at 20kHz ?
Thank you very much and Best Regards