I am looking for ideas to construct a simple jitter measuring set. The frequency I want to measure would be the master clock of a CD player, say 16.9344 MHz. Even better would be to measure the jitter of the DAC latch pulse.
Basically a signal frequency modulated with noise is to be demodulated. The only difference is that the modulation is very low. I found the following FM demodulation methods:
- The dual tuned circuit phase discriminator, where the output amplitude is proportional to the frequency deviation from the center frequency.
- The PLL method. The amplitude of the analog error signal will be proportional to the frequency deviation.
- The scaling demodulator. Here the FM signal is shaped to square wave and constant pulse width. After low-pass filtering we get the analog signal.
For me the PLL method looks most easily realizable. Has anybody experience in this topic?
Further thinking a very narrow band phase discriminator could be realized by using a crystal as a filter, tuned slightly away from the nominal frequency of the signal to be measured. An LP filter must follow.
We now cab measure down to levels below 100fs.
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