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Electro-Mechanical Broadband RF Switch.
• Single-Stage Driver Amplifier •
Quad-Band EDGE Radio Solution • Modeling
3G / WCDMA / HSDPA • Composite Filters
• Integration of Waveguide •
Coaxial Components • Antennas Needed
• And More... |
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New VCO
The CRO2781A-LF in S-band operates at 2780 MHz with a tuning voltage range of 0.5 to 4.5 Vdc. It features a typical phase noise of -115 dBc/Hz @ 10 KHz offset and a typical tuning sensitivity of 9 MHz/V. Its industry standard MINI-16 package is just 0.5 x 0.5 x 0.22".
Wideband PA Module
A new wideband power amplifier module for use in microwave radio, VSAT, military & space, fiber optic and broadband test equipment applications from 100 MHz to 20 GHz has been introduced. The HMC-C057 is a GaAs pHEMT MMIC PA in a miniature hermetic module.
Coaxial to Waveguide Adapters
Coaxial to Waveguide Adapters are offered in a variety of configurations. Option A, broadband adapters, have excellent electrical specs that are maintained over the entire adapter bandwidth. Option B offers enhanced performance over a specific band of the unit’s bandwidth.
Digital Communication Analyzer
The latest addition to the PXIT product family, the PXIT 10G Digital Communication Analyzer (DCA) with Passive Optical Network (PON) filter rate options and smart post processing for the PXIT N2100B DCA, helps optical transceiver test vendors reduce their cost of test.
LED Drivers
This new family of LED driver ICs significantly reduces the number and size of external components required by drive circuits. Operating at switching frequencies up to 600 kHz, AP880X Series step-down, DC-DC converters require only four smaller and lower cost inductors and/or capacitors.
RF Interface DAS Panel
Created to control the output power from PAs, the 15C2NB is designed to combine and attenuate RF signals in steps of 1 dB up to 70 dB of maximum attenuation. With the operating frequency covering 800 MHz to 3 GHz, this design is ready for field deployment for GSM, PCS, WiMAX and LTE network architectures.
Phase-Locked Crystal Oscillator
The PLXO-50 Phase-Locked Crystal Oscillator is used as the frequency reference in a surveillance RADAR application. The PLXO, which operates at 50 MHz, maximizes system performance with its exceptional phase noise (<-150 dBc/Hz @ 10 KHz) and other features.
Directional Antenna
A wide angle 2.4 GHz antenna, model HG2405P-135, is designed for compact installations and is ideal for Wi-Fi, PCS, DCS, and custom applications. It gives the system designer wide angle coverage of an area without multiple antennas or larger footprint antennas.
Band Reject Filters - Tunable
Band stop and cavity filters that can be re-adjusted by the customer to new center frequencies are now available. These filters are tunable over a +/-7.5% center frequency range with minimal change in bandwidth. Operating temperature range is -55 to +85ºC.
Fast Rise/Fall Time Logic
Four new logic devices which are optimized for systems requiring fast rise/fall times, low jitter, and low DC power consumption have been released. They provide operating clock and data rates of 13 GHz/13 Gbps, and are ideal for deployment in ATE, broadband T&M equipment, frequency synthesis and radar signal processing systems.
Ultra Low Phase Noise VCO
Model CRO1220A-LF in L-band operates at 1220 MHz with a tuning voltage range of 0 to 5 Vdc. This VCO features a typical phase noise of -118 dBc/Hz @ 10 KHz offset and a typical tuning sensitivity of 2 MHz/V. It is well suited for satellite communication and microwave radio applications.
Design Verification Test Systems
The GS-9000 Assisted GPS (A-GPS) Design Verification Test systems were designed around the 8960 wireless communications test set’s new A-GPS assistance data messaging test capabilities. The capabilities support A-GPS validation, Total Isotropic Sensitivity testing and A-GPS pre-conformance testing for mobile devices.
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March 2006
AWGN: Still the Great Enabler
By Ed Garcia,
President, Noisewave Corp.
If you've looked inside microwave test equipment recently,
no doubt you've noticed that there is precious little
microwave hardware inside. A great example is the RF power
meter, which is now an almost completely digital instrument,
except for a little RF hardware in the sensor. In this
environment of "RF digitization," a test tool as simple
as Additive White Gaussian Noise (AWGN) would seem to
be ready for archival in the annals of microwave technology
past. Interestingly enough, that's far from the case,
as noise-based testing is as viable as ever.
Noise is certainly a signal we are all familiar with,
mostly with its deleterious effects. For those new to
the positive uses of "white noise," it is a simple but
remarkably versatile signal that has a constant spectral
density (expressed in watts per hertz of bandwidth) with
a Gaussian amplitude distribution. AWGN can be generated
by several sources, but avalanche diodes are the most
common source used in electronic system testing. When
AWGN is injected into the input of a receiver, it can
quickly evaluate receiver performance and other parameters.
AWGN can be used to simulate a complicated modulation
signal, to purposely corrupt an existing signal, as a
reference signal in other applications, and as economical
source of broadband power.
The Great Enabler
In the 1990s, the availability of coaxial noise sources
with precision, traceable outputs allowed some of the
first digital wireless systems (such as IS-95 CDMA) to
be evaluated in signal environments that were a reasonable
approximation of real-world conditions. Today, digitally-generated
waveforms have to a large degree replaced AWGN as signal
stimuli in cellular and PCS testing, but they simply were
not available back when analog systems were transitioning
to digital. So in a sense, noise-based simulation enabled
the development of digital wireless systems that could
withstand dense, hostile signal environments. Today's
wireless systems employ complex digital modulation schemes
that are evaluated with waveforms and signal densities
that are generated digitally and very closely resemble
real-world operating conditions. Like so many stories
of "modernization," the next sentence in this article
would logically read: "digital waveforms have largely
replaced diode-base noise sources as signal stimuli in
receiver testing." It hasn't happened.
The Leap-Frog Effect
As modulation bandwidths of communications systems increase
to accommodate the higher data rates required of high-speed
transmission, the systems become more susceptible to noise
because more noise power is coupled into the signal. At
the highest frequencies and broadest bandwidths, digital
waveforms cannot be clocked accurately or even generated
at all. The answer: diode-based noise sources, which can
have bandwidths greater than 100 GHz and retain their
precise nature throughout this range.
As they have before, digital signal generation techniques
will ultimately catch up, and noise-based simulation will
step aside, its job complete as enabler of another generation
of system testing. When the next generation ultra-broadband
system appears, noise-based simulation will no doubt be
called upon again, followed by its digital alternative,
and so on.
Unique Needs For Noise
Noise-based testing is not limited to wireless signal
simulation, and has long been a staple in noise power
ratio (NPR), bit error rate (BER), carrier-to-noise ratio
(C/N), and noise figure measurements. To accurately make
these measurements, a precision coaxial noise standard
remains essential. For example, noise sources make BER
testing practical because the required number of errors
can be generated quickly. Without the ability to increase
the number and frequency of errors, it could take a week
and a half to obtain the number of errors required to
determine a system's BER.
Noise sources also make excellent solutions for implementing
Built-In Test (BIT), since they are extremely inexpensive
yet provide a precise reference by which receiver performance
can be measured. Tiny circuit board-mounted noise sources
that inject a signal of a precisely-known power level
and spectral distribution can be switched-in and the receiver
can be checked at various points to determine if it is
functioning properly.
Cable model testing presents another application for noise-based
testing. Hybrid fiber coax (HFC) systems deliver signals
over a broad bandwidth, and are susceptible to noise and
adjacent channel distortion. By testing a modem in the
presence of noise generated by a noise source, the system
can be evaluated and modified if necessary with different
levels of filtering and other remedies.
Digitally-generated waveforms may accurately represent
signal conditions, but at very high frequencies and very
broad bandwidths their effectiveness declines while diode-based
noise sources continue to perform satisfactorily. Digitally-generated
stimuli repeat, unlike natural phenomena that are problematic
at times. In encryption applications this repetition issue
can be solved by using a truly random number generator
derived from a Gaussian noise source. In BER, NPR, C/N,
and other standard receiver tests, noise sources remain
a key element of the test system. The amount of information
that can be transmitted through a communications channel
is a function of the signal-to-noise ratio. The world's
persistent hunger for information forces an almost continuous
need to evaluate performance as a function of signal-to-noise
ratio. In short, noise may not be new and flashy, but
it still provides an elegant solution to the problem of
evaluating receiver systems of every type for their ability
to meet both rated specifications and to glimpse how they
will perform in the so called "real world." To paraphrase
Monty Python,
"Noise is not dead yet!"
NOISEWAVE
www.noisewave.com
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