signals in phase - RF Cafe Forums

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wallace0075
Post subject: signals in phase
Unread post Posted: Fri Feb 11, 2005 6:39 am
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Joined: Fri Feb 11, 2005 6:32 am
Posts: 4
hi everybody,

I have a question:
I have two signal generators. I´d like to make two signals 1900MHz with a phase between them. In the generators there is a option where you can chenge the starting phase. If I put this two signals made in a power combiner in your opinion they will be stable in phase. I mean the different phase between them will be always the same. Of course they are syncronized

Thanks in advance, wallace0075


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Guest
Post subject:
Unread postPosted: Fri Feb 11, 2005 9:00 am

The two signals will maintante the same phase difference + the phase error of the splitter. But you can calibrate out the phase error by adjusting the phase of one of the signals to compensate for the phase error of the combiner.


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Guest
Post subject: Phase shift
Unread postPosted: Sat Feb 12, 2005 1:50 pm

Careful!

Just because 2 signals are at the same frequency doesn't mean that the phase shift between them can't vary. Noise in one generator that isn't in the other will show up as a phase shift between the two.

To put it another way: in a phase-locked-loop, the phase error is the signal that provides the feecback which tunes the VCO. So unless the generators use a 3rd order loop, there will be a phase error in each generator, which will change with temperature, voltage, etc.

So you absolutely *MUST* verify that your generators will do what you want.

Good Luck.


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Guest
Post subject:
Unread postPosted: Mon Feb 14, 2005 10:40 am

I thought what wallace was trying to achieve here was to have to signals of same frequency but different phase. Depending on what he has a generator, there are many that are capable of adjusting the phase of the signal. Naturally, he will need to calibrate the signal to cancel out errors in the system.


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Guest
Post subject:
Unread postPosted: Tue Feb 15, 2005 3:43 am

I have an idea abot this.
If I put a trigger with the same frequency of the two signals that I want get, and I sincronyze all, Can I get in the output the two signals stable in phase ??

thanks


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Guest
Post subject:
Unread postPosted: Tue Feb 15, 2005 4:15 am

I have an idea abot this.
If I put a trigger with the same frequency of the two signals that I want get, and I sincronyze all, Can I get in the output the two signals stable in phase ??

thanks




Posted  11/12/2012