Hardware and Software Questions, IF pins activation in STA8089GA

[Armin Choopani]

Hi , as I said in the previous question, I have designed a GNSS module with STA8089GA IC which works properly. It easily determines the 3D position, under two minutes, when I use an active antenna. Also, I use a GNSS simulator to demonstrate its functionality. By setting the simulator on satellite ID 10 with -80 dBm power and 42.5 dB/Hz CN0 and performing @PSTMRFTESTON,10 command on the IC, the CN0 is 43 dB/Hz based on the Teseo-Suite Pro software. The IC I use has two IF (Intermediate Frequency) pins to determines its RF front-end functionality which I want to use them to determines NF (Noise Figure). In the application notes of the IC, it is mentioned that to activate these pins you need to perform a NMEA command. But I cannot find the NMEA command. Does anybody know what is the command to activate these pins?

Also, because the IF pins are differential, a differential to single ampilfer is needed. The amplifier I used is shown in the picture. I want to know, does input impedance of the amplifier can load the IF pins and degrade the overall IC functionality? Should I increase its input impedance?

Any advice or help is appreciated.

Armin

[Francesco Virlinzi]

Hi Armin

We can not provide this kind of information because it's company confidential as you had access to documentation not provided online.

Our suggestion is that you have a general review on the RF-path matching as you should have a CN-0 @ 42 dBm with a -130 dBm input

Regards

Francesco

[Armin Choopani]

Hi Francesco

Thanks for your response and suggestion.

I didn't think that the command for activating IF pins is so confidential. On the other hand, I have to evaluate RF-path whether I know this command or not.

About your suggestion, as you said I use a GPS simulator with CN0 = 42 dBm and Pin = -130 dBm. Based on the software (Teseo-Suite Pro) the received CN0 is 37 dBm. Is this a good sign? Is CN0 = 37 dBm high enough?

Best Regards

Armin

[Francesco Virlinzi]

It should be more... but at the end also 37 dBm is good enough.

Regards

Francesco