How does one feed a two channel transmitter inputs from a tekronix generator ?

[sulymani]

Hey guys

I've done my transmitter. it works fine. But, I need to know how to feed it with input from a generator within taking into account that such a transmitter has two channels R+L. shall i use two different generators to feed every single channel ? I really need some help.

 

[berkeman]

Hey guys

I've done my transmitter. it works fine. But, I need to know how to feed it with input from a generator within taking into account that such a transmitter has two channels R+L. shall i use two different generators to feed every single channel ? I really need some help.

Are you referring to the WiFi transmitter you asked about a while back?

https://www.physicsforums.com/showthread.php?t=215867

What are R+L? Right and Left channels? Is this a stereo something?

If you want to take the one single-ended output from a typical 50 Ohm signal generator, and feed two 50 Ohm single-ended inputs, you can use an RF splitter (the two outputs are about 3dBm down compared to the input). You can make your own splitter with a transformer that woeks in the frequency band of interest. You can also make one with just capacitive coupling, if you don't need a DC component in the signal.

 

[berkeman]

Check out the Power Splitter Application Notes at the bottom of this page at Mini-Circuits:

http://www.minicircuits.com/pages/app_notes.html

 

[sulymani]

Thanks berkeman for ur comments.


dude you kinda misunderstood my question. I meant that i want to test my transmitter using a generator and a spectrum analyzer. Ok, I will need to feed such a transmitter with for example a 10 KHz sine wave from the generator and then I''ll be able to see the modulated signal in the spectrum. My question is for the fact that I am using two channels, How can I feed the both channels with a 10 KHz from one generator ?? becaus all I know that i hook every channel to a different generator with the same 10 KHz. Is there any way to use one ? I hope you got my question ..

 

[Pumblechook]

Just parallel the inputs. All you will see are sidebands at 10 kHz spacing (and 19kHz pilot town). I would guess the TX is hi-z in and the generator is lo-z out so levels will not be affected. Vary the audio level and you will see the individual sidebands change in level. I think at some levels the carrier disappears and this can be used as a crude way (but expensive as it requires a spectrum analyser - suppose a narrow band receiver could be use if the TX is highly stable) of testing performance. --- Bessel functions. Pre-emphasis may complicate things if different auidio freqs are used.

http://www.ycars.org/EFRA/Module%20B/fmanalysis.htm

The proper way of testing a TX is with a demodulator and stereo decoder (with correct de-emphasis or off if TX pre-emp is turned off) of known high performance and test the R and L channels separately for frequency response and linearity. Check channel separation also.

 

[sulymani]

Thanks Pumblechook that's clear enough.