Re: : Re: AW: Airspy architecture

Alberto I2PHD

On 2/2/2015 4:09 PM, sdrsharp@... [airspy] wrote:

The tuner offers two ways for calibrating the IQ balance. One is manual with phase and gain adjustment registers and the other is fully automated. The automated method uses long term correlation between the legit signals and their images to generate error signals. These signals are injected back to the gain stages for gain adjustment, and the phase splitters (Frequency dividers used to generate the IQ LO). The test signals are taken from the RF input. Without this calibration, the image suppression is still good around 40 - 45dB.
The IF filter is adjusted to the samplerate with roll-offs at 500kHz on each side. So it doubles as anti-aliasing filter too.
I hope this helps.



�� thanks for that explanation. Things are becoming more and more clear. You must have access to information
about the innards of that tuner surely much more detailed of what it is freely available on Internet... :-)

73 Alberto I2PHD
Credo Ut Intelligam

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