Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

frequency sampling from RF waves

Status
Not open for further replies.

darkness.signals

Newbie level 4
Joined
Jul 30, 2012
Messages
6
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,327
hi there...
how can i get a frequency sample from RF wave? of course too near by sender(wave generator).
does it work with a PICKUP COIL witch connected to a prescaler unit(sp8704)?
 

The frequency of a wave cannot come alone. It comes with either signal voltage or current. You need a DEVICE connected to an antenna which picks up a sample of wave power, and has terminals on which you can connect a frequency meter, counter, etc. A pickup coil can be such device, but as its diameter is small compared to the wave length, so the signal power to be used would be small, too. A better choice is a half-wave dipole or a directional antenna.

Some frequency counters can measure signal frequency with only a quarter-wave antenna not very far from the transmitting antenna. A power level like -10 dBm is enough for them to measure.
 

thanks...
look my friend...actually i want to detect frequency of a remote control...and this is my plan:
i connect to ends of a dipole to correspond pin on a prescaler unit (sp8704) then to a simple amplifier then to a micro controller!
does it work?

- - - Updated - - -

thanks...
look my friend...actually i want to detect frequency of a remote control...and this is my plan:
i connect to ends of a dipole to correspond pin on a prescaler unit (sp8704) then to a simple amplifier then to a micro controller!
does it work?
 

thanks...
look my friend...actually i want to detect frequency of a remote control...and this is my plan:
i connect to ends of a dipole to correspond pin on a prescaler unit (sp8704) then to a simple amplifier then to a micro controller!
does it work?

- - - Updated - - -

thanks...
look my friend...actually i want to detect frequency of a remote control...and this is my plan:
i connect to ends of a dipole to correspond pin on a prescaler unit (sp8704) then to a simple amplifier then to a micro controller!
does it work?

Maybe your prescaler connected to a dipole could work. You have to try it. Prescalers usually are connected to a coupled oscillator output, so their RF input power is specified in their data sheet.

I have a pocket counter operating from 10 to 3300 MHz; it can work with a quarter-wave dipole if an antenna connected to a RF signal source is up to one meter away.

If your prescaler does not work, it possibly needs a preamplifier, a better antenna or get it closer to a source antenna. You can also use a borrowed spectrum analyzer, or, a receiver tunable to the expected frequency. Using a laboratory instrument is easier than building a special device if you only need once to check the frequency.
 
what's the "prescaler ic" of your pocket counter?

- - - Updated - - -

what's the "prescaler ic" of your pocket counter?
 

I am sorry, I have no access to such details. The pocket counter is Optoelectronics CUB Mini Counter and has all electronics sealed in a block. Its cost is ~ $120.- building a special device would cost you more. I would advise you to try e-bay where similar counters can be available for a low cost, and ready to use.
 

Apart from the signal pick-up problem (should basically work, I think) you might face the problem that the transmitted RF burst of your remote control is too short related to the frequency counter gate time.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top