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Is it possible to recover a 1pWatt signal?

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Advanced Member level 2
Jun 20, 2001
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Does anyone know how, or can point to useful reading material, to recover a signal that has at most 1pWatt of power?

at this low of a level i expect the signal (from a CCD camera) to be burried in noise. any suggestion would be helpful



could use an amplifier and filter , amplifier and filter, etc. to get the signal up to a useable level.

but it would still be lost in noise...



Consider a bandwidth of 5 MHz, this means a noise at the input of the amplifier of -100dBm ( - 174 + [( 20log(10) BW ( 5 MHZ)=74 dB] this with an amplifier with no imput noise figure ( 0dB); 1 pW means - 90 dBm and at the end this means you have only 10 dB S/N at the input of the amplifier.
Considering a noise figure of the amplifier of 2 dB you have at the output of the amplifier a S/N of merely 8 dB, to my experience not enough to view nothing but noise.


Use a Lock-in Amplifier.

Look at the subject of Lock-in Amplifiers.
Start with this Site:

**broken link removed**

I think it is doable.

Good Luck.

unfortunately i need to know if its possible by today! because i must make a decision weither to accept this project or not.

can we take a poll... all in favour?

Depend on the sensor and on the signal bandwidth. For instance the modern bolometric receivers have noise equivalent power of 1E-17 watt/RtHz and signal bandwidth several khz. Of corse you need to cool this thing to 0.3K though, but the 1 pW will be resolved with a signal to noise ratio of 1000 ;)

recovered signal

Yes, looks that with an amplifier cooled is possible to obtain a very low noise figure, but to me seems that the person needs a video amplifier for a video signal ( 5 MHz bandwidth ) and not some tens of KHz, probably it has not to cost too much and possible to build with normal components ( possibly RS for the prototype ); this is the real world.
On the other side if you need a very special amplifier with such characteristics seem to me that an engineer needs more than some days to say if he can accept or not the project and on the other side, before the decision, there is for sure ( unless someone don't want to suicide ) a study for the possibility to build such amplifier or even all the system.
Nobody is so crazy to accept a so complicated project without a preliminary study about feasibility.

agreed. i had only 3 days to decide. in the end i did not feel confident that it could be accomplished easily (even with a big $ budget and lots of time). i have decided to persue a venture in renewable energy instead.

thanks for all your advice



I think you may to try SHF components from Mini-Circuits it's very low noise... Also i think that correct recovery of 5Mhz bandwidth signal with this power, are really but only with digital video processing.

Regards, Jackal.

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