Re: W-FM


jose maria trueba
 

Hi,

75KHz is the nominal frequency deviation of a FM mono broadcast transmission, but now all of them are using stereo mode, adding two 38KHz sub-carriers. Mode is called 256-f3 because (75dev+38stereo+15max_audio_freq)x2 equals 256, nominal bandwidth.

Later they came with RDS, sub-carrier is at 57KHz, resulting a max bandwidth of  (57+75)x2 equal to 264, and filters should be as wide 280KHz. There are some 330KHz filters to be used in cascade with another one. I imagine that some are that wide to give a margin for some over-deviating transmissions.

Let us say that 280KHz@-6dB is a reasonable bandwidth.

73's
Jose

2011/1/4 Simon HB9DRV <simon@...>

 

Hi,

 

No –I’ll maybe add it very soon but need help!

 

What bandwidths are needed? For broadcast I think it’s 100kHz, anyway let me know what typical bandwidths are needed please.

 

You never know – I may even add stereo J

 

 

From: sdr-radio-com@... [mailto:sdr-radio-com@...] On Behalf Of Rob M0TFO
Sent: 04 January 2011 20:10
To: sdr-radio-com@...
Subject: [sdr-radio-com] W-FM

 

 

I may of just missed it,but does sdr-radio support Wide FM?
Rob


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