Background:
Yesterday, I said I will use ZHL-32A for amplifying beat note signal, but as Koji pointed out, ZHL-32A is for medium high power.
So I changed my mind to use ZFL-1000LN instead. ZFL-1000LN is a low noise RF amp whose maximum power is 3dBm.
Also, we included a splitter in our consideration.
What I did:
1. Set up a new setup. ZFL-1000LN has a gain of +24dB at 80MHz and splitter ZFRSC-42 has a loss of -6dB. So;
beat note signal -> ZFL-1000LN -> ZFL-1000LN -> ZFRSC-42 => SR620 and VCO
2. Measured frequency-output relation. When the input signal was 80MHz -48dBm, the output was -8.7dBm. For other frequencies;
60MHz -3.3dBm
70MHz -5.7dBm
80MHz -8.7dBm
90MHz -5.5dBm
100MHz -3.5dBm
So, we can see frequency up to >100MHz by SR620 using this setup.
3. Checked harmonics peak levels of the output using an RF spectrum analyzer. When the input signal was 80MHz -48dBm, the height of the peaks were;
80MHz -8.8dBm
160MHz -30dBm
240MHz -42dBm
Other peaks were smaller than the 3rd harmonics. Also, RF PD that detects beat note signal has a cut-off frequency at around 100MHz. So, we don't need to worry about wave transformation for this setup.
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ZHL-32A is a high power (well..., actually middle power) amplifier with the max output power of +29dBm (~1W!).
It seems to be overkill.
Your signal is so small so you don't need ZHL-32A, but can use small amp which we may have somewhere in the lab.
And the description:
"RF amplifier ZHL-32A has around +28dBm gain at 80MHz"
The unit is wrong.
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Yes. I corrected my previous elog. |