[SOLVED] Looking for a DC-3 GHz RF amplfifer design or module

[hafrse]

Looking for a DC-3 GHz RF amplifier design or module

Hi,

Looking for a DC-3 GHz RF amplifier design or a module to amplify the input signal with 3dbm of a faulty RF deck in my spectrum analyzer.
signal shows 3dbm less than it should on this spectrum analyzer and I thought I could compensate by simply adding an amplifier. The level loss of 3dbm is linear with the amplitude variation.
Thanks

 

[BigBoss]

Since you know the amplitude error of the instrument why don't you add an "amplitude offset" to your SA ? Using an extra amplifier will increase the DANL of the SA.

 

[Warpspeed]

There is most probably an adjustment somewhere for gain in the IF amplifier.
If you have lost 3db everywhere, that is where I would be looking, further along the chain where most of the gain is.

 

[hafrse]

There is most probably an adjustment somewhere for gain in the IF amplifier.
If you have lost 3db everywhere, that is where I would be looking, further along the chain where most of the gain is.

Will try to se if I can do it with a pot on the IF board, have no schematics and the analyzer will not calibrate the IFS block because of the level drop.
Thanks

- - - Updated - - -

Since you know the amplitude error of the instrument why don't you add an "amplitude offset" to your SA ? Using an extra amplifier will increase the DANL of the SA.

Thanks for the info, can you please explain how I can do it ?

 

[BigBoss]

Thanks for the info, can you please explain how I can do it ?

Almost every SA has a such feature.There should essentially be because the man who makes this measurement will use not very well characterized cables and connectors.Therefore, he will make an adjustment or calibration with a well known source.Modern SAs have this feature in order to do this.

 

[hafrse]

Hello,

It is an Advantest 3465 and has a self calibration routine but does not pass becasue of this problem

 

[Warpspeed]

I recently bought an Advantest 3361, I have no idea how similar they may be.

The 3361 uses an internal 30 Mhz calibration signal for self test, and the first thing to do might be to check that the 30 Mhz calibration signal is correct.
The calibration signal is switched right at the input connector with a relay.

If you have a tracking generator, that can also be very useful for comparing the 0dbm tracking generator output with the 0dbm input reference level.

There are multiple gain adjustments in the IF amplifier. In fact when you switch through the various bandwidth selections between 30Hz and 1Mhz, every IF filter has its own individual gain potentiometer.
There are very detailed instructions in the service manual for doing all this if you can locate the appropriate service manual on the internet.

 

[hafrse]

Thanks, no manuals available for this analyzer, I slightly adjusted some pots (2 of them) on the IF output board from the RF deck and got more amplitude (about .8 dbm) after that the self calibration routine completed sucssessfully! now the level is 100% correct!

Thanks again for all help I got

 

[Warpspeed]

Great stuff !