Grosshansdorf, Germany – 1 September 2015Â –Â For applications where low-level electronic signals need to be acquired and analyzed, Spectrum has added a range of pre-amplifiers that can be used to boost signal levels. When combined with a Spectrum digitizer these low noise pre-amplifiers can greatly increase the measurement systems overall dynamic range and sensitivity. The new pre-amplifiers are designed to compliment the built-in amplifiers of the digitizer, effectively extending the available input ranges, and allowing the detection and measurement of much smaller signals.
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Seven different pre-amplifiers are available making it easy to select a model that can best match the digitizer being used. They offer gain ranges from 20Â dB to 60Â dB, bandwidths from 10Â MHz to 2Â GHz as well as 50Â ? and 1Â M? terminations. Most of the pre-amplifiers also have true DC coupling and an adjustable output offset control to further extend their operational use.
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To utilize the resolution and maximize the precision of a digitizer it is important that the signal being measured covers as much of the ADC’s dynamic range as possible. Spectrum digitizers already feature highly configurable input amplifiers that offer a variety of input ranges. However, the new pre-amplifiers extend this even further.
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For example, the 16Â bit M2i.46xx series digitizers come with 8 programmable input settings offering from 50Â mV to 10Â V full scale range. Using an SPA.1231 pre-amplifier can provide an additional gain of either 40Â dB or 60Â dB (x100 or x1000) effectively delivering a Full Scale Range (FSR) that can go as low as 50Â ?V. The low FSR together with the 16Â bit resolution of the digitizer makes it possible to detect signal variations that are way down into the nano-volt range.
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The fastest pre-amplifier SPA.1841 with a bandwidth of 2Â GHz perfectly matches the Spectrum M4i.22xx series digitizers that offer up to 5Â GS/s sampling rate and a bandwidth up to 1.5Â GHz. Using the combination of a M4i.2230-x8 and a SPA.1841 amplifier one can sample signals in the GHz range with a FSR of 2Â mV resulting in a resolution of 15Â ?V per step at the given digitizer resolution of 8Â bit.Â
 The picture shows the acquisition of a 2 mV 40 MHz sine signal with plain digitizer and with digitizer + pre-amplifer in comparison.
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Such high gain often means high noise, especially when amplifying small signals, so careful design of both the digitizer and pre-amplifier is crucial. All SPA series pre-amplifiers are optimized for minimum input noise with models available that reach values as low as 0.9Â nV/?Hz. For applications that need to push the technology even further signal processing functions, such as averaging and filtering, can be used on the digitized data. Such signal processing techniques can help to reduce the effects of random noise and greatly improve the overall signal-to-noise ratio of the measurements being made.
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Please contact info@spec.de for more information or visit our web site at www.spectrum-instrumentation.com
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About Spectrum Systementwicklung Microelectronic GmbH
Spectrum is a pioneer in the design and manufacture of PC based test and measurement instrumentation that is used for electronic signal capture, generation and analysis. The company specializes in high-speed digitizer and generator technology and has available over 400 modular products in the most popular industry standards PCIe, LXI and PXI. The company is headquartered in Grosshansdorf, Germany and sells its products worldwide via an extensive sales network offering outstanding support directly from the design engineers. More information about Spectrum can be found at www.spectrum-instrumentation.com
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