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VCO and CDR for a serializer/transceiver of 1 Gbit/s

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mouzid

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Hello,

For a serializer/Tranceiver of 1 Gbit/s using a pll of 1 Ghz, what should be the frequency of the clock driving the deserilizer/Receiver:
1 Ghz or 2 Ghz ?
 

VCO and CDR

Hi,
I think that If the receiver / tranceiver are synchronous you should use 1 Ghz else you will need a CDR so a 2 Ghz clock.
 

    M

    mouzid

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VCO and CDR

It depends on the type of phase detector you are using. If you are using a full-rate phase detector , then you will need 1GHz clock. If you are using a half-rate PD then you only need a 0.5 GHz clock.
 

    M

    mouzid

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Re: VCO and CDR

Fahmy said:
It depends on the type of phase detector you are using. If you are using a full-rate phase detector , then you will need 1GHz clock. If you are using a half-rate PD then you only need a 0.5 GHz clock.
Click to expand...

Could ypu please Fahmy through more light on Full rate/ Hlaf rate PD ?
Thanks.
 

    M

    mouzid

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Re: VCO and CDR

AdvaRes said:
Fahmy said:
It depends on the type of phase detector you are using. If you are using a full-rate phase detector , then you will need 1GHz clock. If you are using a half-rate PD then you only need a 0.5 GHz clock.
Click to expand...

Could ypu please Fahmy through more light on Full rate/ Hlaf rate PD ?
Thanks.
Click to expand...

Full-rate phase detectors are the conventional phase detectors (like Hogge PD and Alexander PD) these phase detectors operates on a clock with the same frequency of the incoming date (i.e clock frequency= bit rate). On the other hand, half-rate phase detectors are those phase detectors that operates by a VCO working at half the frequency of the incoming data (i.e. clock frequency = 1/2 * bit rate ). This feature is usually realized by taking more extra clocks from the VCO with multiple phases. attached some examples of half-rate PDs.
The main advantage of half-rate phase detectors is relaxing the speed and power contraints on most of the system by operating with a lower frequency.
Sorry for the late reply
 

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