Re: question about TIA
Hi,
In optical communications, the signals are transferred in NRZ coding which is basically on the matter of "1" or "0" switching. So, in order to measure the quality of this signal, some measurement is used to detect it which is called "eye-diagram" tool. Basically eyediagram, is divided into two, i) optical eye-diagram, ii) electrical eyediagram. Optical means, when u measure the signal from the transmitter (TX), and electrical means you meaure the signal after the Receiver (RX) which goes in to CDR(clock and data recovery).
So, basically by using this eye-diagram measurement we can know the noise induced within the circuit which may caused by the electronic devices, PCB traces, wire-bonds, mismatches and so on. Since the NRZ signal is generated randomly, and when there is long runs of bits 1s & 0s, so it will induce different crossing points in the signals, so by using the eye-diagram, we can astually measure the different of the crossings of the signal through jitter as well.
Eye-diagram, is measured through the entire Tx or Rx system not only at TIA.
Regards,
Suria3