Just looking for a very quick ballpark indication, nothing accurate needed.
Is it easy and cheap to build a PLL with one degree resolution of a 30 kHz sinusoidal signal input asuming low pre-detection noise (S/N > 50 dB) and
Thanks, George
50 dB SNR means an instantaneous phase uncertainty of 1/(sqrt(2)*10**2.5) radians, or about 0.13 degree, which is fine. If you know that your signal is always near 30 kHz, you can make a VCO with a restricted range, so that it will pull in very rapidly. (Simple PLLs pull in nice and fast if the frequency offset is less than a few times the loop BW.)
So something like a NE565 or MC14046 can do this, no problems. You'll want to use an op amp in the feedback loop if you use a 565 or the XOR phase detector of the '4046. If the sinusoid is nice and big, you can use the frequency-phase detector in the 4046, which is even easier--no op amp required, no limitation on pull-in range.
Cheers,
Phil Hobbs
(Do they even make 565s any more?)
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