In GRC I have a complex sine source with amplitude 10 and frequency 2000Hz sampled at 4000Hz as a input to the costas loop through a throttle block. The max and min frequency used is +/- 0.157rad/sample which is 100Hz /sample. When I see the output on scope and FFT scope i see peak at 0Hz in the FFt scope but on the oscilloscope I see a sine wave with amplitude 10 on the Inphase component and 0 in the Q component. Why?
The output is shown in the figure. http://img690.imageshack.us/img690/7879/snapshot1u.jpg Thanks On Thu, Feb 4, 2010 at 2:52 PM, Johnathan Corgan < [email protected]> wrote: > On Thu, Feb 4, 2010 at 09:23, Mir M. Ali <[email protected]> wrote: > > > What is expected if I input a costas loop block with a complex sine wave > > signal? Will the Costas track the sine and give me a baseband output > > containing nothing? > > You will get a complex DC value. I will be the magnitude of the input > signal and Q will be 0, plus a small amount of "noise" due to round > off error. > > Johnathan >
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