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7225 Dual Phase DSP Lock-in Amplifier

7225 Lock-in Amplifier
Model 7225 

The SIGNAL RECOVERY model 7225 offers a cost-effective solution to the researcher needing the performance provided by DSP demodulation.

The 7225 is capable of measuring the in-phase and quadrature components, vector magnitude, phase angle and noise of the input signal.

Two auxiliary ADC inputs, four DAC outputs and eight output logic lines are provided.These can be used to record the magnitude of external signals associated with the experiment, such as temperature or pressure, or to generate voltages to control or switch other equipment. Information from the ADCs together with the lock-in amplifier's output data can be stored in the 32k point buffer memory prior to transfer back to a controlling computer.

The 7225 instrument controls are adjusted via the left-hand display panel and its associated keys, while the right hand panel shows the two selected instrument outputs. Auto functions need only two keypresses to activate and in many cases eliminate the need for manual control adjustment.

External control of the unit is via either the RS232 or GPIB interfaces, using simple mnemonic-type ASCII commands. A second RS232 port allows up to sixteen 7225 or compatible instruments to be operated from a single RS232 computer port by connecting them in a “daisy-chain” configuration.

Compatible software is available in the form of a LabVIEW driver supporting all instrument functions, the Acquire lock-in amplifier applications software and the SRInstComms ActiveX control and software toolkit. The driver and a demonstration version of the applications software, DemoAcquire, are available for download from our website.

  • Application Notes +


    TN1000 What is a Lock-in Amplifier?

    TN1003 The Digital Lock-in Amplifier

    AN1001 Input offset reduction using the Synchronous Oscillator Demodulator Monitor on the 7255 7260 and 7265

    AN1002 Using the Model 7225 and 7265 Lock-in Amplifiers with software written for the SR830

  • Instruction Manual +


    Model 7225 User Manual

  • Specifications +


    Input
    Voltage
    Mode A only, -B only or Differential A only, -B only or Differential
    Sensitivity 2 nV to 1 V 2 nV to 1 V
    Impedance
    FET Device 10 MΩ // 30 pF 10 MΩ //30 pF
    Bipolar Device 10 kΩ // 30 pF 10 kΩ// 30 pF
    Noise
    FET Device 5 nV/√Hz at 1 kHz 5 nV/√Hz at 1 kHz
    Bipolar Device 2 nV/√Hz at 1 kHz 2 nV/√Hz at 1 kHz
    C.M.R.R. > 100 dB at 1 kHz > 100 dB at 1 kHz
    Gain Accuracy 0.2% typ (full bandwidth) 0.2% typ (full bandwidth)
    Line Filter attenuates 50, 60, 100, 120 Hz attenuates 50, 60, 100, 120 Hz
    Current
    Mode Low-noise or Wideband Low-noise or Wideband
    Sensitivity
    Low Noise 2 fA to 10 nA 2 fA to 10 nA
    Wideband 2 fA to 1 µA 2 fA to 1 µA
    Impedance
    Low Noise < 2.5 kΩ < 2.5 kΩ
    Wideband < 250 Ω < 250 Ω
    Noise
    Low Noise 13 fA/√Hz 13 fA/√Hz
    Wideband 130 fA/√Hz 130 fA/√Hz
    Gain Accuracy
    Low Noise ≤ 0.6% typ (midband) ≤ 0.6% typ (midband)
    Wideband ≤ 0.6% typ (midband) ≤ 0.6% typ (midband)
    Dynamic Reserve > 100 dB > 100 dB
    Frequency Response 1 mHz to 120 kHz 1 mHz to 250 kHz
    Output
    Fast outputs
    Time constant 10 µs to 640 µs 10 µs to 640 µs
    Outputs available X & Y X & Y or X & MAG
    Voltage for ±full-scale
    input    		 ±2.5 V linear to ±300% f.s. ±2.5 V linear to ±300% f.s.
    Impedance 1 kΩ 1 kΩ
    Update Rate 166 kHz 166 kHz
    Roll-off 6 dB/octave 6 dB/octave
    Other Outputs
    Time constant 5 ms to 100 ks 5 ms to 100 ks
    Outputs available X, Y, R, q, Noise X, Y, R, q, Noise, Ratio, Log Ratio
    Voltage for ±full-scale
    input    		 ±10.0 V linear to ±110% f.s. ±10.0 V linear to ±110 f.s.
    Impedance 1 kΩ 1 kΩ
    Update Rate 200 Hz 200 Hz
    Roll-off 6, 12, 18 and 24 dB/octave 6, 12, 18 and 24 dB/octave
    Oscillator
    Amplitude Range 1 mV to 5 V 1 µV to 5 V
    Amplitude Sweep Linear: computer control only Linear: manual or computer control
    Amplitude Resolution
    1 µV to 4 mV N/A 1 µV
    1 mV to 4 mV 1 mV N/A
    4 mV to 500 mV 1 mV 125 µV
    501 mV to 2 V 4 mV 500 µV
    2.001 V to 5 V 10 mV 1.25 mV
    Frequency Range 1 mHz to 120 kHz 1 mHz to 250 kHz
    Frequency Sweep Linear or Logarithmic: computer control only Linear or Logarithmic: manual or computer control
    Impedance 50 Ω 50 Ω

  • Options +


    Item Model Number
    Rack Mount K02002

  • 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     		Acquire
    Active X Control SRINSTCOMMS