SR830 DSPLock-In Amplifier The SR810 and SR830 have differential inputs with 6 nV/ √ Hzinput noise. The input impedance is 10 M > Ω, and minimumfull-scale input voltage sensitivity is 2 nV. The inputs can also be configured for current measurements with selectable current gains of 10 Input Channel > The SR810 and SR830 DSPLock-In Amplifiers provide highperformance at a reasonable cost. The SR830 simultaneously displays the magnitude and phase of a signal, while the SR810 displays the magnitude only. Both instruments use digital signal processing (DSP) to replace the demodulators, output filters, and amplifiers found in conventional lock-ins. The SR810 and SR830 provide uncompromised performance with an operating range of 1 mHz to 102 kHz and 100 dB of drift-free dynamic reserve. > The dynamic reserve of a lock-in amplifier, at a given full-scale input voltage, is the ratio (in dB) of the largest interfering > 6 and 10 > 8 V/A. Aline filter (50 Hz or 60 Hz) and a 2 ՗ line filter (100 Hz or 120 Hz) are provided toeliminate line related interference. However, unlike conventional lock-in amplifiers, no tracking band-pass filter is needed at the input. This filter is used by conventional lock-ins to increase dynamic reserve. Unfortunately, band pass filters also introduce noise, amplitude and phase error, and drift. TheDSPdesign of these lock-ins has such inherently largedynamic reserve that no band pass filter is needed. Extended Dynamic Reserve > (U.S. list)

Digital Phase Shifting The digital signal processor also handles the task of output filtering, allowing time constants from 10 Analog phase shifting circuits have also been replaced with aDSPcalculation. Phase is measured with 0.01 resolution, and the X and Youtputs are orthogonal to 0.001а. s to 30,000 s witha choice of 6, 12, 18 and 24 dB/oct rolloff. For low frequency measurements (below 200 Hz), synchronous filters can be engaged to notch out multiples of the reference frequency. Since the harmonics of the reference have been eliminated (notably 2F), effective output filtering can be achieved...

Signal Channel OutputsSine, TTL(When using an externalreference, both outputs are phase locked to the external reference.) Channel 14-digit LED display with 40-segment LED bar graph. X, R, X-noise, Aux 1 or Aux 2. The display can also be any of these quantities divided by Aux 1 or Aux 2.Channel 2 (SR830)4ݽ-digit LED display with 40-segment LED bar graph. Y, Voltage inputsSingle-ended or differentialSensitivity2 nVto 1 V Current input10 Displays θ , Y-noise, Aux 3 or Aux 4. The display can also be any of these quantities divided by Aux 3 or Aux 4.OffsetX, Y, R can be offset up to 105 % of full...