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Stanford SR844 200MHz RF Lock-in Amplifier

Home Products Instrumentation Amplifiers and Preamplifiers Stanford SR844 200MHz RF Lock-in Amplifier

Stanford SR844 200MHz RF Lock-in Amplifier

Stanford Research Systems

The SR844 is the widest bandwidth lock-in amplifier available. It provides uncompromised performance with a frequency range of 25kHz to 200MHz and up to 80dB of drift-free reserve. The SR844 includes the many features, ease of operation and programmability that you've come to expect from the Stanford digital lock-in amplifiers.


  • 25kHz to 200MHz frequency range
  • 80dB dynamic reserve
  • Time constants from 100µs to 30ks (6, 12, 18, 24 dB/oct rolloff)
  • "No Time Constant" mode (10 to 20µs update rate)
  • Auto-gain, -phase, -reserve and -offset
  • Internal or external reference
  • Two 16-bit DAC's and ADC's
  • GPIB and RS232 interfaces

The SR844 uses the same advanced DSP technology found in the SR850, SR830 and SR810 lock-in amplifiers. DSP offers many advantages over analog instruments - high dynamic reserve, low zero-drift, accurate RF phase shifts and orthogonality, and digital output filtering.

The SR844 has both 50Ω and 1MΩ. The 1MΩ is used with high source impedances at low frequencies, or with a standard 10x scope probe. the 50Ω input provides the best RF signal matching. Full-scale sensitivities range from 1Vrms (+13dBm) down to 100nVrms (-127dBm). Up to 60dB of RF attenuation or 20dB of RF gain can be selected in 20dB increments. Gain allocation can be optimised to provide up to 80dB of dynamic reserve.

For further information please contact us or download the datasheet.


      SR844 datasheet                                          Read more on Stanford's website