[Discuss-gnuradio] Generating complex exponential stream

[Praveen Vikram]

Hi,

I'am new to GNURadio. I started off writing a few signal processing blocks (since I'am more comfortable with C++ than Python).

So far, I have written a signal block for circular correlation (to get an idea of the entire process) and a signal source that gives off C/A Code samples (to be used with acquisition) and both work as expected.

I'am now trying to use these block in Python and am kinda stuck.

The basic signal flow I'am trying to achieve is as follows:

=====================           ==============        ===============

| File Source       | --------> | Multiplier |------> | Vector Sink |

|                   |           ==============        ===============

=====================                 ^

                                      |

                                      |

    ==============              ==============      

    | CA Samples |------------> | Multiplier | <---- e^{-j*2*pi*fd*t}

    ==============              ==============

The CA samples block, is a source block that take the sampling frequency, and doppler frequency and samples the CA code, accordingly. 

The questions I have are,

1) How do i obtain the time t, to be able to generate e^{-j*2*pi*fd*t}.

2) How do I make sure the multiplier is multiplying the first value from CA samples with the first value of e^{-j*2*pi*fd*t} and so on. Does GNURadio take care of this?

Any help/pointers will be appreciated.

Thanks,

Praveen