My experience with the HP spectrum anaylyzers is that it has about 35dB NF.
You can calculate this from observation *and* from their data sheets.
So if you want the analyzer to not contribute, you need a lot of gain in
front. I'd recommend two stage amplifiers.
Plus, you really have to make certain that tones outside where you're
looking don't get into the amplifier and do weird things to the tones you
are looking at.
-
Robert -
-----Original Message-----
From: Price, Ed <[email protected]>
To: 'John Cronin' <[email protected]>; [email protected]
<[email protected]>
List-Post: [email protected]
Date: Wednesday, August 25, 1999 5:41 PM
Subject: RE: Amplifier for measurements above 1GHz
>
>John:
>
>So you need another 10dB of gain between 1 & 5 GHz. I have used Miteq
>low-noise preamps in the past, but I bought octave-band models and I paid a
>lot extra for absolute lowest noise figure with about 35dB of gain. I
>suggest you call Miteq (get the noise figure of your spectrum analyzer
>first) and see what combinations they recommend. You might need only a 1dB
>noise figure, with about 20dB of gain, which may mean they have one unit
>that can span the frequency range.
>
>Site at: http://www.miteq.com
>
>
>:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-)
>Ed Price
>[email protected]
>Electromagnetic Compatibility Lab
>Cubic Defense Systems
>San Diego, CA. USA
>619-505-2780 (Voice)
>619-505-1502 (Fax)
>Military & Avionics EMC Services Is Our Specialty
>Shake-Bake-Shock - Metrology - Reliability Analysis
>:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-)
>
>> -----Original Message-----
>> From: John Cronin [SMTP:[email protected]]
>> Sent: Wednesday, August 25, 1999 2:50 PM
>> To: [email protected]
>> Subject: Amplifier for measurements above 1GHz
>>
>>
>> I am hoping to purchase a 1 to 5 Ghz amplifier to be used in conjunction
>> with a spectrum analyzer to measure emissions at 3m to FCC requirements.
>> With a 1 MHz bandwidth into a HP microwave analyzer we can only currently
>> measure at 1m.
>>
>> Can we get away with measurements at 1m?
>>
>> Can anyone recommend a low cost microwave amplifier that is suitable for
>> the
>> task?
>>
>> Thanks in anticipation of your response.
>>
>>
>> John Cronin
>>
---------
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