Audio-DSP-Lab 1.7 — the receiver's IF back at 10 kHz

Audio-DSP-Lab 1.7 takes the receiver's default IF back to 10 kHz (1.6 had moved it to 12 kHz). With an I/Q front end, 12 kHz is a quarter of the 48 kHz sample rate, where a front end's third-order products fold exactly onto the image and no I/Q correction removes them: the image null stopped at 56 dB there against 67 dB at 10 kHz. 10 kHz keeps clear of that and of the noise that rises near a front end's oscillator. An IF front end simply sets the IF dial to its own IF.

Downloads

• Audio-DSP-Lab-1.7-windows-x64.zip: the Windows application (self-contained, no .NET needed), the board and panel firmware with the flash tool, the manual and the installation guide.
• Audio-DSP-Lab-firmware-1.7.zip: the firmware alone.

Flash the board with Flash-Firmware.cmd, the front panel with Flash-Panel.cmd (see the installation guide). The protocol is unchanged (version 1).

What's new

Firmware 1.7, protocol 1 (unchanged), application 1.7, panel firmware 1.7.

• Receiver: the IF (protocol parameter offset) starts at 10 kHz again, in the firmware and in the simulator.
• Docs: the manual, the installation guide and the protocol give 10 kHz as the default and explain why; screenshots of the application and the panel at 1.7.

Everything else is as in 1.6: the receiver is a pure backend from the IF on (no front end control in the application), the dial is called IF, and a front end should deliver its signal at K2 at about 1 mV amplitude.