Generating Constant Source for Channel Gain Measurement

[Wired_]

I need a contant source say a DC level which shall I transmit over a channel to get channel gain/ fading over few transmission blocks.

I tried a naive approach of getting a constant by DC_m= m*sin(t)/sint(t) and sin(t)-sin(t) +m

through follwing design.

Though I can see a constant DC in waveform_graph 3 but when I receive the data from RX port of USRP RIO, which I expected to be a faded DC value, I am getting a sign wave whose frequency is dependent on the tone frequency of the Sin wave generator.

I cannot explain this!!

My purpose if to get channel gain between RX-TX pair and TX-Eavedropper pair. Do I need to implement dedicated channel sounder based on PN sequqnece correlator? or this approach of H_ab= Y/X shall work. I negated X as it would need perfect synchronization between RX-TX pair for channel gain estimation.

Any suugestion on the anomaly? Or suggestion on implementing channel gain measurement using Comm suite.

[tcap]

Hello Wired_,

Can you please provide me with a little more information on how you are recording in the TX data? How are you demodulating the signal? Why are you expecting it to be a faded DC value? Which sine wave generator are you referring too? The carrier frequency or the waveform generator VI in LabVIEW?

I would expect the output of the TX to be the carrier frequency tone, with an amplitude dependent on the DC level.

If you have hardware specific questions, I recommend posting them to the SDR forum.

Regards,