Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

how to find the phase of an RF signal

Status
Not open for further replies.

neezaket

Newbie level 1
Joined
Mar 26, 2007
Messages
1
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,291
Hello,
I have an RF signal whose frequency I do not know and I need to find its phase and frequency characteristics.
I have tried iq demodulation.
1- x = input signal
2- take fft of x and find the frequency where the power is maximumand use that value as demodulation frequency.
3-perform iq demodulation. (mix with demod frequency and low pass filtering)
4- find the phase and frequency.

Unfortunately, i can not find the exact frequency of the signal thus there occurs an error in demodulation frequency. This error prevents to find the phase characteristics correctly. For example in order to see the phase constant, phase seems to change linearly.

i hope my explanation is enough. I really need some ideas. maybe i am in a wrong wat for determining the phase characteristicf of an RF signal. Any help is appreciated.
 

FvM

Super Moderator
Staff member
Joined
Jan 22, 2008
Messages
48,419
Helped
14,252
Reputation
28,765
Reaction score
12,942
Trophy points
1,393
Location
Bochum, Germany
Activity points
280,194
I agree that it's necessary to know the basic signal characteristic.

The phase measurement point sounds unclear. If the phase is constant (which would be the case e.g. for a unmodulated carrier or an AM signal), measuring phase is meaningless. For signals with non-constant phase, e.g. phase shift keyed, FM, SSB or DSB with supressed carier, the refernce phase would be usually recovered from the signal itself by a PLL.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top