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7270 General Purpose DSP Lock-in Amplifier

7270 Lock-in Amplifier
Model 7270

The model 7270 sets a new standard for general-purpose DSP lock-in amplifiers. The 7270 is a next generation, much improved version of the 7265. This instrument takes advantage of the developments in technology since the first DSP lock-in amplifiers were introduced in the early 1990’s to update the core design, but made sure that we’ve included all the latest features.  The new architecture has allowed us to offer even better specifications in an instrument that is physically much more compact than older designs. The result is a lock-in amplifier of outstanding performance that is easy to use and suitable for all measurements over a frequency range extending from 1 mHz to 250 kHz.

In common with other models in our range, the 7270 offers much more than just dual phase lock-in detection at the reference frequency of an applied signal. We’ve included features unique to SIGNAL RECOVERY instruments such as dual reference and dual harmonic detection, which allow signals at two different frequencies to be measured simultaneously. The spectral display mode shows the power spectral density of the input signal, making it easy to avoid interfering signals when selecting a reference frequency. It is now even possible to perform tandem demodulation. In this mode an amplitude-modulated signal at a (high) “carrier” frequency is first demodulated at that frequency. The resulting in-phase output, at short time constant settings, is a signal at the modulating frequency which is then passed forward for detection by a second set of demodulators running at the same modulating frequency. Such detection techniques, which can be used in pump-probe measurements, have until now required two separate instruments with an analog connection between them.

Fast Data Processing
The main ADC sampling rate and the rate at which the analog signal outputs are updated is 1 MSa/s, giving excellent performance when used at short output filter time constant settings, such as in scanned probe measurements. But we’ve also increased the maximum rate at which data can be stored to the internal curve buffer to 1 μs per point, allowing for the first time direct capture of instrument outputs when using these short time constants. The buffer length has also been increased to 100,000 sets of points, giving recording times of 100 ms at the fastest sampling rates. What’s more, in the fast capture mode the length does not need to be divided by the number of outputs being stored, making it possible, for example, to store the full 100,000 points of X, Y and auxiliary ADC1 values at the same time.

Remote Control
The built-in RS232, USB and Ethernet connections allow full operation from a controlling computer. We offer a comprehensive software package, Acquire, that can operate the instrument via any of these interfaces and makes it easy to set up and run complex experiments, such as frequency response measurements, as well as allowing remote control of every instrument function. Users who wish to do their own programming can use our ActiveX control and toolkit (SRInstComms), or free LabVIEW driver, to simplify the task.

See what you’ve been missing...
In summary, if you’re looking for a general purpose lock-in to work in the range 1 mHz to 250 kHz then you need look no further - you’ve found it in the SIGNAL RECOVERY model 7270.

  • Documents +

  • Specifications +

    Signal Channel
    Voltage Input
    Modes A only, -B only or Differential (A-B)
    Freq. Response 1 mHz < F < 250 kHz
    Full-scale Sensitivity 2 nV to 1 V in a 1-2-5 sequence (e.g. 2 nV, 5 nV, 10 nV, 20 nV, etc.)
    Z - FET 10 MΩ // 25 pF, AC or DC coupled
    Z - Bipolar 10 kΩ // 25 pF, input must be DC coupled
    Max safe input ±12.0 V
    Vin Noise - FET 5 nV/√Hz @ 1 kHz
    Vin Noise - Bipolar 2 nV/√Hz @ 1 kHz
    C.M.R.R. > 100 dB @ 1 kHz degrading by > 6 dB/octave with increasing frequency
    Gain Accuracy ±0.5% typ, ±1.0% max
    Distortion -90 dB THD (60 dB AC gain, 1 kHz)
    Current Input
    Mode Low Noise (10E8 V/A) or Wide Bandwidth (10E6 V/A)
    Full-scale Sensitivity
    Low Noise 2 fA to 10 nA in a 1-2-5 sequence
    Wide Bandwidth 2 fA to 1 µA in a 1-2-5 sequence
    Frequency Response (-3 dB):
    Low Noise 1 mHz < F < 500 Hz minimum
    Wide Bandwidth 1 mHz < F < 50 kHz minimum
    Low Noise < 2.5 kΩ @ 100 Hz
    Wide Bandwidth < 250 Ω @ 1 kHz
    Low Noise 13 fA/√Hz @ 500 Hz
    Wide Bandwidth 130 fA/√Hz @ 1 kHz
    Gain Accuracy ±2.0% typ, midband
    Max. Dynamic Reserve > 100 dB
    Grounding BNC shield can be grounded or floated via 1 kΩ to ground
    Signal Monitor Amplitude ±1 V FS
    Output Impedance 1 kΩ
    Reference Channel
    Reference Input
    Frequency Range 1 mHz to 250 kHz
    Analog Input (front panel)
    Impedance 1 MΩ // 30 pF
    Sinusoidal Input Level 1.0 V rms*
    Frequency Range 0.5 Hz to 250 kHz
    Squarewave Input Level 250 mV rms
    Frequency Range 2 Hz to 250 kHz
    Reference Channel
    Phase Set Resolution 0.001° increments
    Phase Noise at 100 ms TC, 12 dB/octave slope:
    Internal Reference < 0.0001° rms
    External Reference < 0.01° rms @ 1 kHz
    Orthogonality 90° ± 0.0001°
    Acquisition Time
    Internal Reference instantaneous
    External Reference 2 cycles + 1 s
    Demodulator and Output Processing
    Harmonic Rejection -90 dB
    Output Filters
    Time Constant 10 µs to 100 ks in a 1-2-5 sequence
    Slope (roll-off):
    TC < 5 ms 6 or 12 dB/octave
    TC > 5 ms 6, 12, 18 or 24 dB/octave
    Synchronous Filter Available for F < 20 Hz
    Offset Auto and Manual on X and/or Y: ±300% full-scale
    Phase Measurement Resolution < 0.01º
    Oscillator - General
    Freq. Range 1 mHz to 250 kHz
    Setting Resolution 1 mHz
    Absolute Accuracy ± 50 ppm
    Amplitude Range 1 µV to 5 V
    Max. Setting Resolution 1 µV
    Output Impedance 50 Ω
    Frequency Sweep
    Output Range 1 mHz to 250 kHz
    Law Linear or Logarithmic
    Step Rate 1 kHz maximum (1 ms/step)
    Amplitude Sweep
    Output Range 0.000 to 1.000 V rms
    Law Linear
    Step Rate 20 Hz maximum (50 ms/step)
    Oscillator Output
    Accuracy ±0.2% typ
    Stability 50 ppm/ºC
    Distortion (THD) -80 dB @ 1 kHz and 100 mV rms
    Data Storage Buffer
    Size 100,000 data points
    Max. Storage Rate
    Fast Mode up to 1 MHz (X1, Y1, X2, Y2, ADC1, Demod I/P 1, Demod I/P 2)
    Normal Mode 1 kHz
    User Settings
    Up to 8 complete instrument settings can be saved or recalled at will from non-volatile memory
    USB 2.0, Ethernet, and RS232 allow complete control of instrument settings, and data readout.
    Power Requirements
    Voltage 110/120/220/240 VAC
    Frequency 50/60 Hz
    Power 40 VA max
    Width 15½" (390 mm)
    Depth 7¼" (185 mm)
    With feet 7¼" (185 mm)
    Without feet 6½" (170 mm)
    Weight 12.8 lb (5.8 kg)
    Specifications subject to change without notice
  • Options +

    Item Model Number
    Rack Mount K02005
  • Software +

    Item Model Number
    Acquire Software
    The software includes a powerful plotting engine that lets you show data just as you want it using a variety of line styles, allows data export to both text and CSV files, offers comprehensive clipboard support, and includes a context-sensitive help system
    Active X Control SRINSTCOMMS