RF detector help - Page 1
Forum section: electronics / rf-microwave

author: Cacao
author_rank: Contributor
timestamp: July 12, 2017, 03:35:27 pm
content: Just gonna ask question about detecting RF signal. Will this certain IC will be effective on detecting any signal?? and will connecting an open ended coaxial probe as an antenna in the RF input work??Thanks in advance.LTC5535 datasheet:http://cds.linear.com/docs/en/datasheet/5535f.pdf

author: ChristofferB
author_rank: Frequent Contributor
timestamp: July 12, 2017, 05:04:11 pm
content: "Any" signal is a pretty broad concept. It will detect signals in the range and freq. given in the datasheet. It will probably detect something with just a bit of wire sticking out, but it all depends on what you want to see. I've had a similar log. detector chip on a small board with a little dipole on for relative measurements, and that did pick up some signals, but depending on what it is, you may want to put a LNA in front of it.

author: Ian.M
author_rank: Super Contributor
timestamp: July 12, 2017, 05:09:26 pm
content: Also its an AM detector. Don't expect any joy with a weaker FM or FSK signal.It also may misbehave if you try to operate it a long way below its lower specified frequency limit of 600MHz, so unless your only interest is UHF upwards, its either the wrong chip for the job, or for a one-off project you'll need to test and calibrate it for lower frequencies.

author: Cacao
author_rank: Contributor
timestamp: July 14, 2017, 03:36:33 pm
content: Quote from: ChristofferB on July 12, 2017, 05:04:11 pmI plan to detect microwave signals that has been transmitted thru an open ended coaxial cable. Will it work?

author: MikeLogix
author_rank: Contributor
timestamp: July 15, 2017, 11:20:56 pm
content: Quote from: Ian.M on July 12, 2017, 05:09:26 pmIt is just a power detector. It does not matter what the modulation type is.

author: CJay
author_rank: Super Contributor
timestamp: July 17, 2017, 11:10:10 am
content: Umm, seems 'detector' is a confusing term to use but I have a suspicion the log detector ICs could function as a demodulator for AM/SSB signals. They would of course be useless for demodulating FM/PSK and of course their primary purpose is for power measurement

author: Cacao
author_rank: Contributor
timestamp: August 13, 2017, 05:31:14 pm
content: Quote from: MikeLogix on July 15, 2017, 11:20:56 pmEven if it is just a simple microwave signal that has not been modulated and just travel along copper?

author: retrolefty
author_rank: Super Contributor
timestamp: August 13, 2017, 09:39:37 pm
content: Quote from: Cacao on August 13, 2017, 05:31:14 pmYes, it will detect unmodulated RF signals within it's dynamic and frequency range. Note that this will not provide a 'power' measurement but rather a voltage level measurement. There are log amp type RF power detectors with larger dynamic range and dbm linear DC output. Review your desired frequency range and min and max signal level requirement, you might find a better chipfor your requirements.

author: Cacao
author_rank: Contributor
timestamp: August 14, 2017, 01:30:30 am
content: Quote from: retrolefty on August 13, 2017, 09:39:37 pmthank you very much