Why modulation and demodulation with PXI-5673 and PXI-5663 was wrong%3F

[zainabmaghraby]

iam using PSK-demodulation-modulation  example found in find examples to perform modulation-demodulation for the transmitted signal iam using PXIe-5673 and PXIe-5663 as VSG-VSA 

i found that the received bits not as the transmitted bits any help in this issue

[mudson]

Hello zainabmaghraby,

Could you post the following:

• Bits transmitted
• Bits received
• Screenshots of the Front Panels for your Transmit and Receive code, including the Constellations
• The code you're using for Transmission and Receiving

We will be better able to assist in hunting down the problem with that information.

[zainabmaghraby]

iam sending PN sequence or user defined pattern 01010101 

the received is not as the transmitted 

here i attach the code

[mudson]

Hello zainabmaghraby,

Thank you for the VIs and the text file.

When you send out 01010101 what do you get back out on the demodulation VI?

Could you provide a screenshot of your generation VI, and your acquisition VI while they are running?  It will be helpful to see what settings are being used on both sides of the transmission.  

It will also be helpful to see the IQ constellation.

It may also be worth your while to setup some synch bits so the two sides of your system have an easier time knowing where messages begin and end.

Best regards,

[JÞB]

If I recall.  There is a IIR filter down in the MT guts in that example. (a few layers down inside mod_contineous-BB-PSK)  You need to run the vi twice to preload the IIR filter or suffer the impulse (since the IIR filter resets to a initial value of 0 and you really want a magnitude ON the imaginary plane unit circle for PSK to work right)

I don't have the TK installed but mudson should be able to find the nagging little filter for you from the discription.