Other Parts Discussed in Thread: DS25BR100EVK, DS25CP102,
Hi,
I am currently using DS25BR100EVK evaluation board in order to evaluate pre-emphasis and egalisation performances.
In the pre-emphasis paragraph of your application note AN-1957 (LVDS Signal conditioners Reduce Data-Dependent Jitter), we can see the waveform of a 2.5Gbps PRBS-7 signal measured at the output of the DS25CP102 with pre-emphasis disabled and with pre-emphasis enabled:
I can see the 6dB gain the DS25CP102 provides when the pre-emphasis is enabled (and also the 0dB gain at low frequency).
I assume that DS25BR120 has the same "type of preemphasis" (high pass filter with a 3dB, 6dB or 9dB gain at 1.56Ghz).
At first, I tested the component without transmission loss in order to see the pre-emphasis effect on the output.
I used a 2.304Gbps PRBS7 data signal input and measured this on the oscillosope:
First picture shows the output of DS25BR120 without pre-emphasis and the second one shows the output of DS25BR120 with a medium pre-emphasis (6dB).
I don't see the 6dB gain. I am not working at the optimal frequency (1.56GHz) but I am assuming that i should see a gain very close to 6dB when working at 1.15GHz ?
On top of that, I can see a static gain which I am not supposed to see.
Please help me out to understand why I obtain this measurement ?
Do you have the pre-emphasis frequency response ?
Thank you,
Gladys
I use a 1.15GHz PRBS7 data input signal an