[Discuss-gnuradio] How to reset the phase for subsequent sweeps from VCO?

[khalid.el-darymli]

Hi,

I am using the VCO block in GRC to generate complex-valued sweeps with BW of 50 KHz and a sweep time of 1 second. The VCO is driven by the  sawtooth signal generator in GRC.

The problem I am facing is that subsequent sweeps do not start at the same time. Each new sweep seems to have a random phase shift relevant to the other. Please see the attached figure which demonstrates the case for seven subsequent sweeps. This figure was generated in Matlab after saving the output of VCO to a binary file in GRC. Then, for the sampling frequency of 50 KHz, individual sweeps were resolved and superimposed on each other.

My question is, how do I reset the phase of the VCO at the beginning of each new sweep?

Thank you.

Best regards,
Khalid

SevenSweeps.png
Description: PNG image