Calculating noise figure of handheld radio

[Qacer]

I'm trying to figure out how a Noise Figure value for a handheld radio was derived. Here is the mathematical relationship used:

Radio sensitivity (-120 dBm) minus S/N (5 dB) minus Bandwidth (43 dB-Hz) minus thermal noise (-174 dBm/Hz) equals Noise Figure (6 dB)

The radio sensitivity of -120 dBm is in the spec sheet. The thermal noise of -174 dBm/Hz is a known value derived from assuming room temperature and for 1Hz bandwidth. However, I do not know how the S/N and Bandwidth values were derived. The modulation type is frequency shift keying (FSK). Frequency range is in VHF.

I was told that the S/N and bandwidth were typical values. But I could not find any references.

Thanks!

 

[Hitman928]

Do you have a link to the data sheet?

 

[Qacer]

http://www.motorolasolutions.com/co...s/_staticfiles/en_dp4000_4pp_specsheet_v2.pdf

This is not the right spec sheet because I don't have it on this computer. Anyway, the parameters in the spec sheet above are similar, so I just need a way to figure out the noise figure from the parameters given.

 

[Hitman928]

Is this for a school assignment?

 

[Qacer]

Not homework.

I think I figured it out. All I can say is that rounding values can throw one off sometimes. The actual dB value for the channel bandwidth is actually 43.98, but somehow, they rounded it down to 43.

The The S/N value was determined via a bit error rate vs. energy per bit to noise power spectral density ratio chart for FSK.

Also, the noise figure equations assume room temperature at 17 Celsius. But for this application "room" temperature is more like 5 Celsius, so I think this should be the value used rather than the textbook 17 C value.