Hi everyone,I want to make a Carrier recovery circuit(not simulation,actual circiut) for bpsk which input signal will be at 300Mhz or more(maybe Ghz).Is it possible?I dont care about what using to utilize it dsp,fpga ,anything is good for me as long as it works.I have seen HSP50210 Digital Costas Loop but is works at very low frequency for what i want.Should i use it and down convert the signal before using it?Any help would be very appreciated!!!
Down-converting would work if the bit rate is low relative to the carrier.
One way to do it directly is to double the signal (with, say, a Mini-Circuits diode-mixer type doubler) and bandpass filter the resulting 600 MHz. Then divide by two and adjust for the ambiguity.
John
Look at digital RF subsystems at AD, TI, Intersil web sites.
Vladimir Vassilevsky DSP and Mixed Signal Design Consultant
The Costas loop will have somewhat better noise than the squaring loop that John suggested, but squaring is a lot easier to implement. It's worth looking in a classical PLL reference (my favourite is Gardner's 'Phaselock techniques') for the analogue versions.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
What everyone else said, plus some random comments:
The baud rate is almost more important than the carrier frequency for this kind of stuff.
If you have a low baud rate and a high carrier frequency you may find it convenient to downconvert. If your baud rate is fairly fixed but your carrier frequency may change from time to time (do you have a sales department?) then you'll make your life easier by going to a superheterodyne circuit _now_ -- this will let you separate the data decoding part from the frequency-specific RF part.
This is not rocket science if you know PLL circuits. Someone has already mentioned Floyd Gardner's PLL book; let me also recommend "Phase Locked Loop Circuit Design" by Wolaver. I think it's pretty clear as textbooks go, and (for me at least) strikes a nice balance between enough theory so you're not stumbling around in the dark yet enough practice so that when you get into the lab you know how to put those components together to get something working.
-- www.wescottdesign.com
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