Anoter question for CMU200 users here. I am still playing aroud with my "new" CMU200, and just discovered the following:
when I set the signal generator to for example -27 dbm @2400Mhz, and sent this signal to a 50 ohm dummy load, the signal appears as a -50 dbm peak on the spectrum analyzer (altough no connection is made to the RF input). This seems very high to me, but I have no experience with this kind of RF equipment. It does not matter which of the two RF inputs or outputs I configure, I always get approxemately the same result. Is this normal or do I have a damaged unit?
It sounds like a defective RF matrix. Unless you setup input and output to the same port (RF 1 or RF 2) then you shouldn't see the transmitted signal on the SA if the output signal is that low and the output is indeed properly terminated.
But I'll give it a try on mine tonight to be sure.
Update: Did a quick check on a CMU200 and a CRTU with a -27dBm 2.4GHz CW signal going via a H&S RF cable into my standalone SA (R&S FSP7), with the following results:
- Output RF 1, input RF 2 (50ohms terminated): -47dBm
- Output RF 1, input RF 4 (50ohms terminated): -57dBm
- Output RF 3, input RF 1 (50ohms terminated): -67dBm
I probably didn't notice it before because I never used these devices in that way. It's a bit disappointing that the RF matrix doesn't offer a better channel separation, but I guess it's OK for the purpose these devices were designed for, and in practical terms it shouldn't matter when using either generator or SA, or when looking at a different frequency on the SA than the one set on the generator.
Another alternative could be to disconnect the receiver or transmitter from the RF matrix and connect directly to the module.