Synthesized Signal Generator (SSG)

So many jobs in the lab  require a good quality synthesized RF signal generator used solely as a CW source. Most generators come equipped with programmable digital modulation, analog modulation, external modulation inputs, markers, sweep functions, signal encoding, 100 plus dB dynamic range, etc., and these features may never be used! The SSG is designed to be a workhorse in the lab, providing a high quality synthesized output in a small package that is easy to move around, and without the penalty of paying for features you don't need.

Settling time is typically 50 times faster than other general purpose synthesizers, so it is ideal for high speed, high volume production testing. Frequency and amplitude controls are via the front panel and LAN, GPIB, and RS232.

The SLE700 can be configured with 1, 2, or 4 channels. The bandwidth of each channel is 45 MHz, and the nominal center frequency can be 70 MHz or 140 MHz.  Parameters can be set to fixed values in Static mode, or continuously changed in real time in Dynamic mode without any phase discontinuities. Ephemeris data files are downloaded via an ethernet connection and stored internally in solid state memory. These dynamic files can have playback rates from 1 Hz to 1000 Hz, and  can be run forward, reverse, continuously looped, or single stepped.

Remote control can be accomplished by making calls from your test software, or by using the SleControl application program provided with the instrument. This application provides control of all SLE functions, as well as manipulation of the dynamic data files.

Static and Dynamic Mode Views in the SleControl Ethernet Application

The CNG-70/140 is a fully automated test instrument that sets and maintains a highly accurate ratio between a user-supplied carrier and internally generated White Guassian noise. The instrument operates over a wide range of power levels. The modular design provides one or two totally independent channels covering 50 to 180 MHz. The instrument utilizes dBm's proprietary microprocessor controlled attenuator with 0.015 dB resolution, so resolution uncertainty is less than 0.008 dB. Typical attenuator error is less than 0.02 dB over its entire frequency range and attenuation range.  The CNG corrects for noise density and signal level variations over frequency, and integrates the actual noise power over the user defined signal bandwidth. The carrier signal path is never interrupted.

The CNG-1-800/2700 covers  800 to 2700 MHz, with the same accuracy as our 70/140 MHz units! In the CNG-1-800/2700, noise generation, attenuation, and power measurements are done at IF, so there is no degradation to ratio accuracy.   Total noise bandwidth is 125 MHz, wide enough for virtually every application while still providing a high noise power spectral density.

The WGN outputs very accurate, high quality white Gaussian noise. The output level can be set as Noise Density or Noise Power in a selectable bandwidth. Factory calibration over the entire frequency range yields 0.25 dB absolute accuracy. The noise power can be varied with 0.015 dB resolution over a 95 dB range. Any user supplied signal can be injected into the instrument to combine with the noise. An optional signal attenuator is available. The instrument utilizes dBm's proprietary microprocessor controlled attenuator with 0.015 dB resolution, providing an extremely accurate output.

dBm's frequency converter models cover virtually any band up to 30 GHz. They are available as block converters, synthesized broadband converters, and RF to baseband converters. Instantaneous bandwidth is typically 100 MHz in both up and down conversions. Some standard frequency bands are  800 - 2700 MHz, 870 - 1750 MHz, and ultra-broadband 400 MHz - 18 GHz with IF frequencies of 70 MHz or 140 MHz.

This is an example of an RF interface used to perform inter-operability testing with multiple diversity base stations.

dBm is able to design a broad range of interfaces that provide connectivity and automation for complex test system. These interfaces can include signal conditioning and routing, switching, and signal injection.

dBm's synthesized sources include frequency synthesizers, phase locked oscillators, and digitally tuned oscillators with broadband modulation ports. We specialize in fast switching, broadband designs.

dBm's SSA series attenuators cover up to 3 GHz. They are all solid state designs with 1 dB resolution. Switching time is 1000 times faster than relay type attenuators, and reliability and repeatability are outstanding. Power consumption is extremely low.

These solid state attenuators can also be configured in groups of up to 16. An addressable 8 bit parallel driver card provides a simple control interface. The interface is double buffered, so attenuation channels can be set individually, or all changed simulataneously.