RFFC5071 chip LO signal

RF Solutions RF All Other (switches, controls, attenuators, ..)
1

Hi

I would like to view LO signal by setting bypass bit to 1 in DEV_CTRL in RFFC5071. I can see LO signal in spectrum analyzer. But when I send it to signal counter TF960 6GHz counter, that LO signal cannot be read but TF960 shows other signal values. Is there a way we can increase amplitude of LO signal so that TF960 can easily detect LO signal. How can frequency counter easily detect LO signal?

Best regards
Thanks

2

It could be the counter is locking onto a LO harmonic. What LO output power do you measure on the spectrum analyzer? Is should be around 0dBm to +3dBm, but it will depend on the LO frequency and the frequency response of the mixer output balun (and tuning). You may need to filter the LO signal, and even amplify it dependent on the input level your counter needs. What frequency does your counter lock onto, is it consistent? If you change the mixer bias current setting, MIX_IDD1 or 2, then this should increase the LO output slightly.

3

Hi Chris,

LO generates 1675, 1815 and 2065MHz frequencies and all can be seen in spectrum analyzer. problem is that frequency counter reads harmonics. How to solve this?

4

You could try adding a LPF (or BPF) on the LO output to reduce the harmonics.