from N2EA...
>
> How do you distinguish between a 180 degree phase shift,
> and polarity reversal? Unless you're timing logic edges,
> or counting cycles, they look the same to me.
>
Jim,
If the waveform is symmetrical (like the sine waves of RF), there is no
difference between a "flip" of polarity and a 180 degree delay -- other than
a small loss in the delay line or phase-inverting transformer.
If you have digital signals, there may be variations in the positions of
rising and falling edges, and a delay of 1/2 of the period will be a
different from an inverted version of the data stream. In the RF realm, this
might be an issue in the design of digital circuitry to generate square-wave
drive for a high dynamic range balanced mixer.
73, Gary
K9AY
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