Dear Zahra,

welcome,

You need to compare your received bit stream with its corresponding transmitted bit using digital comparative which may be simply an x-or such that when the two corresponding bits have the same value the output of the x-or will be zero when the two input bits are different the output of the x-or will be logic 1. Counting the the one for a specific number of input bits will make it possible to calculate the bit error rate. Assume the number of input bits =Ni and the number of corresponding error bits=Ne, then the bit error rate will be= Ne/Ni,

So you needs two counters one for the input bits and one for the output bits.

In order to be successful you to synchronize the received data with transmitted data to same clock. You also would like to synchronize the counter to the same clock.

So you have to derive all rates from a master or reference clock and synchronize the received data with same clock.

So, the solution simply is in synchronizing the received data with the transmitted data.

May there is an other solution, in which you transmit a known binary file from the computer through a serial interface by your transceiver, then receive the same file from the output of your communication transceiver and store it in computer as a received file. By comparing the two files one can get the number of bits in error in the file from which one can calculate the bit error rate. You can use the hyper terminal in window for example.

Best wishes

Thank you so much Abdelhalim, I get a lot of good ideas from that. I want also to know which type of link should I use to get data, I used serial but because my produced data is not in serial format(it is bunch of random data(PRBS5)) and serial port should get true start and stop bit to accept the data, serial method was not true. Some recommend me to use FTDI chips (for example SPI protocol), but I want some detailed information about the type of chip should I use and protocol and maybe the code should I write...

Dear Zahra,

All you need is to add a serial port to the input of your transmitter and a serial port to the output of your receiver. The serial port required is the RS232C. You need only to add an IC to convert from TTL to RSc32C format. Yo need only to use the RS232C in its simplest of three wire cable.

Then you can carry out the test by inserting your interfaced transceiver between two laptops or PCs and the file using the hyper terminal as i explained previously.

As an example, you can use the chip in the link or any other equivalent chip for interfacing between the serial port and your transceiver:https://para.maximintegrated.com/en/results.mvp?fam=rs232&793=12.

Best wishes

but I think it cannot be true with serial port. I did this and I did not get good match between transmitted and received data. I think the reason was because I produce random data that was not in serial port protocol and it does not have true start and stop bit, so serial port when get my random data and check its start and stop bit, that bits were not true start and stop bits and does not get my data.

Zahra you can send an alphabetical file and see how it appears at the output of the receiver. You can try to send data under ideal transmission conditions, then the received data will be identical to the transmitted data.

We tested our transceivers with ideal transmission conditions using this method. If not you have to analyse your signal to trouble shoot the malfunctioning part.

Any how the first solution which i introduced in the first part of my first post may work well.

Best wishes

thank you so much dear Abdelhalim:)

Dear Zarah,

Did I understand right: You use PRBS5 Sequence and after tranferring your data the sequence contains some bit errors ?

There is a mechanism to synchronize on these PRBS itself and detect the errored bits itself in the receive side. For this you need no further info from tx side, only the Prbs data stream even with errors.

If this would help i can look for more details

Hi,

if I understand your experiment, you want to send the generated data using a serial port. The RS232 mentioned by you has its own protocol. The start and stop bit do not the transmitted data. The workflow of the RS232 port generates these bits themselves and, on the receiving side, the receiver protocol again removes the start and stop bits from the transmitted data.

The problem may be the speed of data generation and RS232 bandwidth (limited speed).

You can compare the input and output data of your experiment with the XOR circuit. If the coincident input and output bits are different, the XOR circuit will generate logic output 1. If you divide the number of logic 1 at the XOR output by the number of tranferred bits, you get the percentage of error tranferred bits.