After completion of my latest DAC project, I am pondering new and exciting ways to waste my spare time 🙂.
I am thinking about building something to measure audio-band jitter in digital audio interfaces. (People always talk about jitter here, but there hardly any measurements to go with the talk 🙁. )
This is how I see it:
DIR1703 in bare-bones configuration recovers interface clock from digital input (Toslink or coax). Local VCXO is phase-locked to the recovered MCLK from DIR with fairly wide PLL loop bandwidth (10kHz). Jitter in audio frequency band is demodulated by PFD detector (ADF4001, probably) and is now present on the control input of the VCXO. Amplified jitter signal is measured by an ADC, after which RMS or spectrum can be calculated by an MCU and output on a display (or you can send analog signal straight to headphones for subjective evaluations).
Any thoughts?
I am thinking about building something to measure audio-band jitter in digital audio interfaces. (People always talk about jitter here, but there hardly any measurements to go with the talk 🙁. )
This is how I see it:
DIR1703 in bare-bones configuration recovers interface clock from digital input (Toslink or coax). Local VCXO is phase-locked to the recovered MCLK from DIR with fairly wide PLL loop bandwidth (10kHz). Jitter in audio frequency band is demodulated by PFD detector (ADF4001, probably) and is now present on the control input of the VCXO. Amplified jitter signal is measured by an ADC, after which RMS or spectrum can be calculated by an MCU and output on a display (or you can send analog signal straight to headphones for subjective evaluations).
Any thoughts?
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