Signal and Pulse Generator for I/Q balance and Noise Blanker Calibration
(special for Linrad Smart Blankler)
One the most power full tools embedded in Linrad is the Smart Blanker, unfortunate this NB need a fine calibration "in situ", means each audio card associated with the respective SDR HW need to be calibrated. Not everybody has a pulse generator with the characteristics you need and most of the commercial function Generator with a pulse option don't work properly.
With noisy neighborhoods, pulse noise coming from cheap LED lamps, Switching power supplies, LCD computer displays and Wi-Fi our usefull spectrum is heavly disturbed. The Linrad Smart Blanker probe to be a "noise killer" and today a lot of people is looking how to calibrate the smart blanker with relative success.
Leif, SM5BSZ propose in his homage a simple pulse generator to calibrate the Linrad smart blanker.
I already implement this pulse generator and works great, I test different SDR HW like IQ+ and WSE boxes with different audio cards like Delta44, MAYA44, DMx6Fire, EMU1616pcie and the new card from M-Audio M-Track Quad (all card with 4 analog inputs). I was able to calibrate the smart blanker in all situations following the excellent video Leif publish in YouTube.
But the smart blanker calibrations is not the only one you need, previous you need to do I/Q amplitude and phase correction and for that you need a signal generator with some kind of decent signal (in quality). Unfortunate again not everybody has a signal generator for that.
To help people with the calibration routines I decide to implement the SIGP-1, this would be a "Signal Generator AND Pulse Generator" in one single PCB. The signal generator would be a "light version" of the IQ+ LO, I already use an IQ+ LO as a signal generator and I/Q calibration was done perfect. To control the signal generator I use the free software CFSGR tool, no automatic sweep but you can configure the mouse wheel in steps and do manually. The signal generator would have a maximum power of aprox. 0dBm. means you will need to attenuate the signal aprox. 30dB for example if you want to calibrate Linrad with an IQ+ radio.
I WILL NOT PRODUCE FINAL UNITS, I have already the design propose by Leif and my signal gen design in one single diagram, I will build PCB's and I will sale only pcb's and documentation. As a contribution I will provide some parts like the impedance transformer, the si570 and the Attiny microprocessor already programed, the rest you could by in your local electronic store.
If you are interested send me and email, I need at least 20 people, then a PCB per unit will cost much less.