What kind of modulation is used in this waveform?

B

bravehamid

New Member

• Apr 13, 2020

• #1

In the XBEE module datasheet, it is mentioned that the Moore modulation used in it is FSK, but the spectrum observed is as follows. Which modulation is related to this shape?

 

crutschow

Well-Known Member

Most Helpful Member

• Apr 13, 2020

• #2

What is "Moore modulation"?

 

RadioRon

Well-Known Member

• Apr 13, 2020

• #3

Which XBEE module model number?

Radio Emission Designation And Modulation Type For Digi RF Radios | Digi International

www.digi.com

 

B

bravehamid

New Member

• Apr 13, 2020

• #4

XTP9B-DPS-001

 

B

bravehamid

New Member

• Apr 13, 2020

• #5

I'm sorry. I meant B-FSK modulation

 

RadioRon

Well-Known Member

• Apr 13, 2020

• #6

what is the frequency span of your spectrum plot?

 

B

bravehamid

New Member

• Apr 13, 2020

• #7

Bandwidth=300Khz
and Span equal with 500Khz

 

RadioRon

Well-Known Member

• Apr 14, 2020

• #8

Well, the spectrum is not familiar to me. It doesn't look like the kinds of FSK that I have worked with. It is hard to guess the modulation characteristics from this sort of picture. If the total span of the screen is 500KHz, then I assume each horz division is 62.5 KHz which means that those sidebands are equally spaced at about 8.9 KHz apart, and with higher power sidebands at 89 KHz before the level drops away. Are those numbers close to anything familiar in your expectation?

 

B

bravehamid

New Member

• Apr 14, 2020

• #9

You were almost right.
The side bands are about 12.5 kHz(These side bands are not repeated in all waveforms, )but,there is a peak in all the waveforms in the 125 kHz band.
My datarate is 115,200 kbps and has a frequencyhopping of 902-928 MHz.