Paper Info
Title
A 45nm low-power SAW-less WCDMA transmit modulator using direct quadrature voltage modulation
Abstract
To address the low-noise low-power requirement of the WCDMA transmitter this paper describes an innovative approach using direct quadrature voltage modulation via a passive voltage mixer driven by a 25%-duty-cycle LO. As shown in Fig. 6.5.2, first the IF l/Q voltage inputs are filtered by the passive LPF to lower the far-out noise. By switching on/off the transistors M1 to M4 through the quadrature-phased LO with 25% duty cycle, the filtered IF quadrature input voltages Vl+, VQ+, Vl-, and VQ-. are sequentially copied to the voltage mixer output, which sees the high input impedance of the PA driver. Such operation leads to a direct quadrature voltage modulation. The output of the voltage mixer contains both the desired fundamental LO mixing product, and the unwanted odd-harmonic LO mixing products. For a packaged device the unwanted harmonics can be attenuated below -40dBc by a harmonic filter (formed by the RF output bonding wire and capacitors) after the PA driver.
Year
DOI
Venue
2009
10.1109/ISSCC.2009.4977337
ISSCC
Keywords
Field
DocType
size 45 nm,pa driver,harmonic filter,power amplifiers,lo mixing product,low-power saw-less wcdma transmit modulator,direct quadrature voltage modulation,code division multiple access,modulators,surface acoustic waves,passive voltage mixer,spread spectrum communication,modulation,noise,switches,duty cycle,transmitters
Noise floor,Computer science,Voltage,Frequency offset,Duplexer,Electronic engineering,Modulation,Code division multiple access,Electrical engineering,Offset (computer science),Spread spectrum
Conference
ISBN
Citations 
PageRank 
978-1-4244-3458-9
9
1.57
References 
Authors
3
2
Name
Order
Citations
PageRank
Xin He1264.95
Jan van Sinderen26015.38