Bridge12 FMS – Frequency Measuring System for THz Sources

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The Bridge12 FMS is a high-precision precision frequency measurement system to measure and/or track the output frequency of terahertz (THz) sources, such as traveling wave tubes (TWTs) or gyrotrons. The Bridge12 FMS enables you to:

  • Measure the frequency of most THz sources
  • Track a gyrotron’s or TWT’s output frequency throughout the experiment
  • Troubleshoot DNP NMR and other experiments to eliminate frequency issues

Complete your experiment successfully and on time

Whether you’ve built your own THz source or using a commercial device, gyrotrons and TWTs are sensitive instruments that can change their frequency even due to simple changes of the room temperature. Troubleshooting an experiment can be challenging when you don’t have a way to measure THz radiation.

The Bridge12 FMS helps you eliminate a common source of errors from your experiments so you can complete your measurement successfully and on time.

Focus on your core expertise: Your research

As a scientist, you are tempted to build your own instrumentation. The question to ask yourself is whether this is the fastest way to complete your primary goal – your research? Developing your homegrown systems can sidetrack you from your main projects and make it difficult to train other team members to run or even maintain equipment – and because you’re building a system for the first time, it may turn out to be more expensive than an off-the-shelf device.

The Bridge12 FMS is a turn-key frequency measuring system that enables you to focus on your actual work. Because it is well documented and supported, you’ve ensured that research isn’t impacted even as specialists for home-built solutions leave your group.

Because Bridge12 has optimized its production of the FMS, the system is available at a fraction of the price that most work­groups will spend on building a custom solution.

A heterodyne receiver with a broad frequency range

The Bridge12 FMS is a heterodyne receiver based on a sub-harmonic mixer that can measure frequencies from about 26 GHz up to 500 GHz, depending on the input mixer.

The system uses an internal, tunable LO  microwave source and the precise frequency of this source (νLO) is measured using an internal frequency counter. The output of the mixer is a down-converted signal (νIF), which is amplified prior to being recorded by the built-in spectrum analyzer.

To determine the unknown frequency of the THz source (νRF) the frequency of the local oscillator (νLO) is tuned such that the n-th harmonic of the harmonic mixer down-converts the incoming signal to an intermediate frequency (νIF) within the IF bandwidth of the Bridge12 FMS. This signal is then measured in real-time using an internal spectrum analyzer.

Simple Control Software for Measuring and Tracking

The Bridge12 FMS comes with simple, user-friendly control software for measuring and tracking frequencies. Simply install the software package on your gyrotron control system, spectrometer console, or any other Windows computer. The software has two operation modes:

  • Measure: Determine an unknown frequency
  • Track: Track a frequency over a time.



Technical Specifications

  • Frequency Range: 140 – 220 GHz (Other frequency ranges are available, minimum pulse width > 50 ms)
  • Maximum Input Power: + 20 dBm (100 mW)
  • Minimum Signal Sensitivity: 0 dBm (1 mW; at 200 GHz)
  • Accuracy: +/- 0.007 * n GHz (n = harmonic number)
  • Typical LO Frequency Range: 8 – 20 GHz
  • IF Bandwidth: 150 – 1000 MHz
  • System Size (W x H x D): 10.2 x 5.1 x 11.8 (inch), 26 x 13 x 30 (cm)
  • System Weight: 9.4 lbs (4.3 kg)
  • Input Power: 110 V / 50 Hz
  • USB 2.0
  • Control Software: Windows 7/8 (32/64 bit) or higher

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Have a question?

If you have questions about our instrumentation or how we can help you, please contact us.