Title :
A novel wideband active feedback amplifier linearization scheme suitable for handsets
Author :
Nesimoglu, T. ; Canagarajah, C.N. ; McGeehan, J.P. ; Wilkinson, R.J.
Author_Institution :
Centre for Commun. Res., Bristol Univ., UK
Abstract :
A new active feedback network is proposed for reducing intermodulation distortion (IMD). It is based on using the existing second harmonic zone (SHZ) distortion energy generated by the amplifier to predistort the input signals optimally to obtain a linear output. The technique is analyzed theoretically and practical results demonstrate the linearization performance. The measured two-tone test showed 23-dB reduction in the third-order intermodulation products (IMP3), where π/4 DQPSK and W-CDMA gave up to 15-dB and 13-dB adjacent channel interference (ACI) suppression respectively. This technique differs from available active feedback techniques by performing both with narrow and wideband modulated signals. The linearization circuitry is simple and small in size
Keywords :
UHF amplifiers; active networks; adjacent channel interference; code division multiple access; differential phase shift keying; feedback amplifiers; interference suppression; intermodulation distortion; linearisation techniques; mobile radio; quadrature phase shift keying; telephone sets; wideband amplifiers; π/4 DQPSK; 440 MHz; 450 MHz; IMD reduction; UHF; W-CDMA; active feedback network; adjacent channel interference suppression; handsets; input signal predistortion; intermodulation distortion reduction; linearization circuitry; linearization performance; measured two-tone test; narrowband modulated signals; second harmonic zone distortion energy; third-order intermodulation products; wideband active feedback amplifier linearization; wideband modulated signals; Broadband amplifiers; Distortion measurement; Feedback amplifiers; Harmonic distortion; Interchannel interference; Intermodulation distortion; Multiaccess communication; Performance analysis; Signal generators; Testing;
Conference_Titel :
Vehicular Technology Conference Proceedings, 2000. VTC 2000-Spring Tokyo. 2000 IEEE 51st
Conference_Location :
Tokyo
Print_ISBN :
0-7803-5718-3
DOI :
10.1109/VETECS.2000.851564
