[help] About processing gain in CDMA

[currentmirror2000]

processing gain

Hi all,

i want to know when and why to include the processing gain Gp in CDMA in the following calculation:

1) noise figure
2) phase noise
3) ip3

thank you

c.m.

 

[vfone]

processing gain in cdma

The Processing Gain in a spread spectrum receiver system would affect the Signal-to-Noise Ratio and NF requirements.
Here you can find receiver sensitivity equations for a Spread Spectrum system.
**broken link removed**

 

[currentmirror2000]

cdma processing gain

thanks vfone, but it does not explain whether the processing gain has effect in the calculations of 2) phase noise and 3) ip3.

 

[toonafishy]

processing gain cdma

Processing gain doesn't affect noise figure, IP3 or phase noise. However, when you are calculating the receiver sensitivity, noise figure and processing gain directly affect the sensitivity.

Sin (dBm) = NF (dB) + KTBRF (dBm) + Eb/No (dB) - PG (dB)

The effect of IP3 and phase noise depend on the type of system and it is more complicated to determine the effect on the receiver sensitivity. If you are trying to receive a QPSK signal with no interferers, then phase noise and IP3 aren't too important. If you are trying to decode a 256 QAM signal in a crowded band, then they are very important contributers to the receiver sensitivity.