Re: Galileo Frequency Shifting and Filtering

[Marcus Müller]

Hi David,

On 28.02.23 17:17, David Dima wrote:

Dear Marcus, all

Thank you for your response. You are right, I will try to better explain the problem:

Well, when I record the signals separately (for example E5b) as shown in the below picture, and after that I try to process the file containing the IQ samples by means of GNSS-SDR free-tool, I can parse the messages to generate ephemeris, almanac or Rinex files. Even if E5b bandwidth is 25MHz, it works sampling at 20 MHz.

You're losing 1/5 of the relevant spectrum. That doesn't mean it *can't* work, it's just unnecessarily bad – honestly, **why** are you using a sampling rate that's not fit to represent the *full* signal? Can you please state *reasons*?

The issue comes when I try to record both signals at the same time. Taking into account the suggestions Jim, Daniel and you have given me in the forum, I have made a couple of changes in the program resulting in:

Now, at least I think I am closer to getting what I need but I am not sure if there are more mistakes in the flowgraph. So, I have tried to record the signals according to the above flowgraph but after that I still cannot read any signal from the satellites whereas if I record them separately I can.

This makes no sense at all. Where do your "Center Frequencies" in the Freq.-Xlating filters come from?

Best regards,
Marcus