Thanks for your response. I am struggling with this. I still have
trouble visualizing how a 180 or 270 degree change can occur in a
single rf cycle and be able to overcome the "inertia" (probably a
poor choice of words) of the rf circuits , feed line and antenna
system. These are large abrupt changes, not more suttle changes like
i would expect relative to voice modulation. I have read that in some
amplifiers the tank provides the other half of a single rf cycle. Why
wouldnt the same the action interfere with a phase shift in a rf
cycle. I could understand being able to detect a phase shift after a
given period of time with respect to a previous period. The period
being relatively long compared to the rf cycle time.

Gary
W4AF



Roy Lewallen wrote in message ...
Although the bandwidth of a phase modulated signal is theoretically
infinite, the vast majority of the energy is in a finite bandwidth. So
if you filter signal components beyond that bandwidth, you can still
recover the modulation information adequately. What you have to do,
then, is to design the tank circuit so its response isn't too narrow to
pass the modulation information. If it is too narrow, it will decrease
and distort the modulating phase shift.

If you were to build a tank circuit that acted as a perfect "flywheel",
i.e., had zero bandwidth, you wouldn't even be able to pass a code or
voice waveform through it -- everything would come out as a single
frequency, single amplitude sine wave, or nothing at all. (It would also
take an infinite time for it to respond to a signal.) For amplifying
some very broadband types of signals, tank and other tuned circuits are
avoided altogether.

Roy Lewallen, W7EL

gary wrote:
Can someone explain to me how a rf carrier that is phase shift
modulated, for lets say digital transmission, can be amplified in an
amp with a tank circuit output. Why doesnt the tank "flywheel effect"
prohibit or inhibit the abrupt phase changes in the signal. thanks
73

Gary
W4AF