ECE1390 RF L2 - Metrics and Wireless Standards.pdf

Matching

  • evaluated in terms of reflection coefficient
  • good if amplitude of reflected wave to incident wave -10dB

Noise

ECE1390 RF L2 - Metrix and Wireless Standards-1759790181679.png

  • noise refers to noise introduced by the RX
  • Noise Figure () is the ratio of SNR at the input to the SNR at the output
    • inversely of percent input noise at output
  • Noise Factor () = 10log(nf)
  • a RX has power spectral density -174 dBm/Hz

ECE1390 RF L2 - Metrix and Wireless Standards-1759792825703.png

  • Noise Floor () represents minimum noise achievable at the RX input
  • is the minimum signal delectable, limited by and

Distortion

ECE1390 RF L2 - Metrix and Wireless Standards-1759793383705.png

Weak Distortion

  • input:

  • output:

  • fundamental:

  • 3rd order inter-modulation (IM3) =

ECE1390 RF L2 - Metrix and Wireless Standards-1759794236957.png

  • 1dB compression is where fundamental drops 1dB

  • IP3, used to characterize distortion, is extrapolated to , where

  • and

  • inter-modulation products from blockers degrade the output SNR

  • spurious free dynamic range (SFDR)

ECE1390 RF L2 - Metrix and Wireless Standards-1759796196617.png

Local Oscillator Phase Noise

  • Phase Noise spectral density is evaluated a a frequency offset from the carrier
  • mixing with LO with blocker creates noise inside signal bandwidth

Efficiency

  • drain efficiency:

  • power added efficiency:

  • PAE takes into account the input signal power

Adjacent Channel Leakage Ratio (ACLR)

ECE1390 RF L2 - Metrix and Wireless Standards-1759819697174.png

  • ACLR is ratio of transmitted power to adjacent channel power