use network analyzer as clock source for eye measurement?

[olinn]

Hi,

I am new to communication testing. I want to measure eye diagram for a 10Gb/s optical receiver. The common approach is to feed an optical modulator with PRBS patterns from a pattern generator input from a 10Gb/s clock source and use the optical modulator to modulate optical signal for DUT (the optical receiver) and measure DUT output with DCA. Can I use the network analyzer output signal as the clock source for the pattern generator? I am trying to save money for purchasing a clock generator or a microwave synthesizer. Thanks for your help!

 

[VEBill]

Probably.

I presume that you already have a particular network analyzer in mind (one available to you). Using the brand and model number, find the user manual. If it's possible to employ it as a simple clock source, then it's very likely that the manual will have a section explaining how.

 

[VEBill]

PS: it'll be single frequency (sin wave) output, not clock pulses. Also the output amplitude will probably be something like up to +10dBm max.

 

[olinn]

Thanks for both your information! Yes. I have an old HP 8722C network analyzer up to 20GHz. The max. output is 10dBm. Does it mean the Vpp is sqrt(2*0.01W*50Ohm) = 1V ? I checked a HP 70843A pattern generator which accepts 0.45~0.9V Vpp. So I guess voltage should be okey. VE1BLL, you mentioned that VNA is sin wave output. Does clock has to be pulses or square wave? I somehow remember I read about pattern generator can accept sin wave clock but I can't find it in HP70843A's specs sheet.

 

[VEBill]

If you recall EE101, a square wave includes the odd harmonics. Getting up to the GHz range it becomes increasingly difficult to include them. The RF world generally doesn't like harmonics.

You'll need to consider cable loss. At GHz range every foot counts.

Don't forget equipment rental. If your time is worth anything, then renting the exact equipment you need might be better, faster, cheaper.

 

[olinn]

Thanks for the tips!