Not clear about the usage of NIRFSG_ATTR_ANALOG_MODULATION_AM_SENSITIVITY for NI 5654 with 5696

[liHY]

HI

When I was trying to achieve analog modulation(AM) with the functions in NI RFSG，I noticed that there was a function named  NIRFSG_ATTR_ANALOG_MODULATION_AM_SENSITIVITY. I'm

 not totally understand what the SENSITIVITY  means because through the description in the help document, it’s not the same as we metioned in characteristic index of instruments. So, if I'm using a NI 5654 with NI 5696, does this SENSITIVITY matter with achieving AM modulation?

 Thanks a lot!

[mbb25 · Accepted solution]

On most instruments, I think you'd specify the modulation depth.  On the NI 5654 with 5696, AM modulation support is uncalibrated.  Setting the AM sensitivity scales the DAC that affects the modulation depth, but the same sensitivity setting can result in different modulation depths at different frequencies.

The default value is 100, so you are not required to set this to get AM modulation to work.  Reducing the AM sensitivity is functionally equivalent to reducing scale of the signal at the AM In port.

Also note that AM sensitivity may be coerced by the driver to prevent a full scale signal at the AM In port from overdriving the signal power from the 5654 to the 5696.  Reading the AM sensitivity property will indicate the coerced value.  If coercion is preventing you from getting the desired modulation depth, you may need to increase the signal at the AM In port.  The signal at the AM In port must not exceed +/- 2 V DC.

[liHY]

Thank you for your kindly reply, it's very helpful!