THE dBm White Gaussian Noise Generator series instruments generate additive white gaussian noise at levels that can be very accurately set in terms of noise power in a specified bandwidth. They are available from Scientific Devices Aust Pty Ltd .
A 'smart" temperature stabilised attenuator with resolution better then 0.016dB provides extremely accurate and repeatable programming of output noise power.
The instrument offers as standard a signal combiner (10dB total signal path attenuation) with low amplitude and phase ripple to allow the user to easily inject a signal and add it to the internally generated noise. Thus different carrier/noise ratios can easily be set.
An optional signal path attenuator can be used to set the signal power independently of the noise power. Once a C/N ratio is established, the WGN's precision noise attenuator can be used to vary the noise power to set new C/N ratios without having to recalibrate.
A front panel display and intuitive keypad allow the instrument to be controlled from the front panel. The display indicates the center frequency, noise power, noise density, bandwidth, signal attenuation, signal step size and noise step size. Up to ten instrument "states" can be stored in onboard non-volatile memory and recalled at a later time, thus allowing canned tests to be simply and efficiently implemented. An IEEE 488.2 interface is also provided for remote operation.
The WGN is modular in construction. Each module is factory calibrated making drop-in field replacements simple. To solve the problem of attenuator accuracy and reliability, dBm has designed self-compensating all solid state attenuators that correct for frequency and power setting variations.
Typical applications include:
_ Bit error rate (BER) and SINAD testing
_ Component and subsystem linearity characterisation
_ Wireless link emulation
_ Calibrated noise density over entire operating frequency
_ Noise power/bandwidth and noise density control
_ Solid state noise attenuator with 0.016 dB resolution
_ Non-volatile memory for storage/recall of instrument settings