Comparing windows for multitone suppression
Nov 1, 2004
By Raghavendra G. Kulkarni Harmonic interference suppression requires windows with fast decaying sidelobes. When the requirement is to keep peak sidelobes low, Harris windows are preferred; but when the mainlobes are to be of minimum widths, the recently published Kulkarni windows offer a good choice....
Power supply and ground design for WiFi transceiver
Nov 1, 2004
By Roger Bremer, Tracey Chavers, Zhongmin Yu A solid RF layout requires careful planning of board stack-up, power supply routing, supply bypassing, and grounding. These techniques, along with correct placement of filter components, can address PLL spurs as demonstrated by an IEEE-902.11a/g transceiver reference design....
Using advanced signal analysis to identify sources of WLAN transmitter degradations
Oct 1, 2004
By Christian Olgaard Design engineers can use measurements of the error vector magnitude, frequency
error, phase noise, and the transmit power envelope to identify the sources of
degraded WLAN transmitter performance. In particular, techniques are described
to identify and troubleshoot the impacts of amplitude, phase, and group delay
imbalances between the I and Q channels, phase noise, spurious signals and
transient effects, and signal compression on transmitter performance....
Active mixer differential to single-ended IF matching
Aug 1, 2004
By Tom Schiltz While single-ended RF and LO input ports are becoming standard on high
linearity active mixer ICs, integration of the IF output transformer is difficult and
can be undesirable. A discrete balun approach delivers good performance over
a relatively narrow IF bandwidth when compared to a transformer-based IF
matching technique....
Fast Rayleigh Fading Simulation with an IIR Filter and Polyphase Interpolation
Jul 1, 2004
By Christos Komninakis and Joel F. Kirshman This simulator efficiently generates correlated complex Gaussian variates with a
U-shaped power spectral density. It consists of a fixed IIR filter followed by a
variable polyphase interpolator, to accommodate different Doppler rates
specified by the user. The complex Rayleigh fading simulator is implemented as
a model in the Visual System Simulator....
Unique RF front end allows high TOI
Jun 1, 2004
By Roy Keeney and Eiji Mori Signal analyzers are the instruments of choice for characterizing and measuring today's complex digitally modulated signals. Many required measurements...
New Broadband EMC Double-Ridge Guide Horn Antenna
May 1, 2004
By Vicente Rodriguez Traditionally the
antenna parameter of interest to the EMC engineer was the antenna factor. The
advent of higher frequency testing has brought the development of a new
double-ridge guide horn design....
Locator beacon design for victims in distress
Mar 1, 2004
By Fred Mohamadi A multiband radar beacon locates victims in distress during search and rescue missions. The beacon can also help provide ordinance's accurate delivery...
How to debug a PLL frequency synthesizer
Feb 1, 2004
By Bob Kelly Radio systems incorporate frequency synthesizers based on phase lock loop (PLL) technology for various reasons. The benefits of PLLs include: The ease...
