Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
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My Hobby Website:
Phase shifting of a Signal - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
platforms dominating public commenting venues. RF Cafe Forums began sometime around
August of 2003 and was quite well-attended for many years. By 2010, Facebook and
Twitter were overwhelmingly dominating online personal interaction, and RF Cafe
Forums activity dropped off precipitously. If the folks at
phpBB would release a version with integrated
sign-in from the major social media platforms, I would resurrect the RF Cafe Forums,
but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
|-- Amateur Radio
Gripes & Humor
-- CAE, CAD, &
Test & Measurement
Post subject: Phase shifting of a Signal Posted: Tue
Nov 01, 2005 3:31 am
How do you shift the Phase of an analog signal.
With digital its so easy, you just put a delay of couple of usecs
and you get a phase shifted signal.
How do you do it in analog?
Post subject: Analog phase shiftPosted:
Tue Nov 01, 2005 2:22 pm
There are several ways of shifting the
phase of an analog signal:
1. Use the appropriate length of cable:
90 degrees is one-quarter wavelength (don't forget to include the velocity
factor of the cable!)
2. Artificial delay lines are also a possibility
at frequencies low enough that a piece of cable would be unreasonably
long. These simulate a piece of cable by series / parallel C circuits,
cascaded. Other kinds of LC networks are also possible if you don't
want constant time delay.
3. RC Networks: the phase shift is
45 degrees at f = 1/(2 pi RC) for a simple two-component high-pass or
low-pass. More complicated networks can be used to shape phase as a
function of frequency.
Obviously, some techniques (RC) are lossy,
some (transmission lines) have very little loss.
Post subject: Posted: Wed Nov 02,
2005 1:37 pm
Are you aware of any manufactureres that make Delay
lines for analog signals. It should be variable delay, not one of those
fixed -10%, 20% delays.
Post subject: Phase ShiftPosted: Thu Nov 03, 2005 1:30 am
checked their recent catalogs, but Data Delay Devices Inc. used to make
Post subject: Posted: Thu Nov 10, 2005 2:12 pm
i found a new way
- using an all pass filter to delay the phase. I can change the phase
by varying the resistace. Only problem is the output amplitude is not
constant at my frequency - 6Mhz.
It works fine in the Khz range.