Friday, July 12, 2019

New updates for SDR#, libairspyhf and Airspy HF+ (Discovery) Firmware

Airspy has announced the latest releases of SDR# r1702, libairspyhf r1.5.0 and Airspy HF+ Firmware r2.4.0. 

Here's a summary of the changes:

The FM Stereo flag was added in the SDR# API: FmPilotIsDetected.

A new experimental Low-IF mode at a lower sample rate (256ksps IQ) was added across the chain to allow portable devices to operate smoothly without requiring further DC/IQ correction or frequency translation. This mode is considered "experimental" because the AGC has yet to be optimized to accommodate for the smaller bandwidth, but it is already usable as-is with the AGC always on. 

For the curious types, 256ksps Low-IF was obtained by shifting the IF, adding a narrower channel filter and decimating 768ksps by 3. This gives a wonderful number that is a multiple of a known sound card standard rate: 32kHz.

The IQ streaming and command handling were optimized to allow all of this processing to happen. A positive side effect is that the streaming is no longer interrupted by the commands (set frequency, gain, etc.) - and this one is not experimental.

SDR# r1.0.0.1702 :

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