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About Timed Data Collecter

Question asked by spine on Dec 2, 2005
Latest reply on Dec 5, 2005 by kkladopoulos
Hi friends,

I am doing a direct conversion system simulation using Ptolemy. One strange problem I encountered is about Timed Data Collecter:

I build up the RF chain with proper gain and frequency setting, simulate the BER performance and observe the demodulated data from Timed Data collecter. Everything looks OK. But when I add a capacitor after the downconversion mixer to simulate the issue of removing DC-offset, BER did not change much but the data display from Timed Data Collecter becomes very very samll, some number at e-14 compared to 2V without capacitor. I don't know why it is like this.

Then I thought of adding a ADC between the demodulated signal and the Timed Data Collecter, now the displayed data is between 1V and 2V, compared to the reference data, only the phase is 180 different(reversed). I try to change the gain setting of the receive chain, sometimes the data from Timed Data Collecter are all constant of 2V, but BER no change, why? I am using BER IS to measure the BER performance.

One more question is do I need to use ADC to observe the demodulated data? The example for ADC I downloaded from Agilent's website is ZAP format, how can I open it?

thanks for your reply.

best regards,

spine  

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