[time-nuts] DIY TimePod

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Jun 14 04:26:00 EDT 2016

Examples of using 1-2 bit digitisers are radio astronomy receivers or some GPS receivers where the signal is essentially noise or the signal is buried in noise.
If this were to be useful, then at least 2 channels per signal, each channel having its own independent noise source, would be required.  


    On Tuesday, 14 June 2016 6:01 PM, Chris Caudle <chris at chriscaudle.org> wrote:

 On Mon, June 13, 2016 9:38 pm, Bruce Griffiths wrote:
> If the quantisation noise is random and spread uniformly over the Nyquist
> bandwidth (~40MHz??) then the noise floor is about -82dBc/Hz.

How do you spread the quantization noise randomly with a one bit
quantizer?  I'm mostly familiar with single bit quanitizers in the context
of audio range delta-sigma converters where the quantizer is in a feedback
loop to move most of the noise to a higher frequency range. That also
requires a clock much higher than the minimum nyquist requirement.

Maybe I need to see a block diagram of what is being described.  Where is
the clock for the ECL flip-flop generated?  I don't recall seeing a
description of what the effective sample rate will be, or the highest
clock signal accepted for analysis.

> With a high resolution RF ADC internal noise is usually sufficient
> (>= 1 lsb)) to ensure this.

Can't really dither to >= 1lsb when lsb=msb (single bit quantizer).

Chris Caudle

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