Skip to content

7265 Dual Phase DSP Lock-in Amplifier

7265 operates to 250 kHz with dual reference, dual harmonics to 20 kHz  

Our lock-in amplifier software

  • Highlights +

    • Frequency Range up to 250 kHz
    • Dual reference and dual harmonic detection to 20 kHz allow signals at two different frequencies to be measured simultaneously
    • Internal, External references
    • Computer-controlled or full front panel
    • GPIB, RS232 control

  • Lock-in Amplifiers +

    Lock-in Amplifiers
    Signal Recovery originated from the Princeton Applied Research, EG&G products for scientific instrumentation.  They are the inventors of the lock-in amplifier.  A lock-in amplifier is an instrument with dual capability.  It can recover signals in the presence of an overwhelming noise background or, alternatively, it can provide high resolution measurements of relatively clean signals over several orders of magnitude and frequency.
  • Software +

    Acquire Data Acquisition Software

    Compatible Instruments:  Acquire will operate the current SIGNAL RECOVERY Models:  7124, 7225, 7230, 7265, 7270, and 7280
    As well as the legacy models:  4161A, 5105, 5113, 5210 and others.
    Up to ten instruments can be operated simultaneously.

    Acquire is a comprehensive data acquisition package designed to operate most current and many former SIGNAL RECOVERY instruments from a personal computer. It is suitable for use with all our lock-in amplifiers, boxcar averager, and 5113 preamplifier, and operates via Ethernet, USB, RS232, or GPIB (IEEE-488) interfaces. For most users, the software eliminates the need for them to write control software, so that they can concentrate on the task of taking data. It will also prove invaluable for others who simply want to operate an instrument from a remote location or who wish to integrate their instrument with other computer controlled systems. Up to ten instruments can be controlled at the same time.

    The package provides two principal modes of operation. First, in remote front panel mode virtually all of the functions of the connected instrument(s) can be controlled from the computer via a series of simple dialogs. The software is instrument sensitive and adjusts the content of these dialogs automatically to reflect the measurement capabilities and functions available in the connected unit. The data outputs to be displayed can be chosen from the range available and these are then clearly shown on-screen.

    The second mode, experiment recording, allows selected instrument outputs to be recorded as a function of time, with the additional option of sweeping certain outputs (e.g. oscillator frequency, auxiliary DAC voltage, digital filter frequency, digital delay and/or digital port setting) as the experiment proceeds. When used with a lock-in amplifier, any auxiliary ADC inputs can be configured as trigger inputs, allowing data to be logged as function of external trigger events.

    As data is acquired, it is displayed on screen and can be printed, as well as being saved for later use. Displayed plots can use a variety of line formats, while four curve cursors allow direct readout of measured values. However, with the very wide range of applications in which SIGNAL RECOVERY instruments can be used, it is not possible to anticipate every possible format in which the acquired data will be displayed. Hence many users take advantage of the export function to save the data to disk for display and/or further manipulation using other software.

    A comprehensive help system is built in and free support is available to registered users.


    SRInstComms is an ActiveX control that allows users of SIGNAL RECOVERY instruments to control them from PC’s running Windows Operating Systems. The requirement is that these programs must be written in a language that supports such controls, which in practice is virtually all modern languages capable of developing Windows applications. 

    The control takes care of all communication between the user-developed program and the instrument, performing the necessary handshaking and decoding status signals over the selected interface, which can be GPIB, RS232, Ethernet or USB, depending on the type of interface fitted to the instrument being controlled. With the exception of speed, the interface type is essentially transparent to the user, making programs portable between systems with different interfaces. 

    It includes an automatic search routine which will find any compatible instruments that are connected to the computer. In most cases, this eliminates the need to adjust the communications settings controls on the instrument. The complete “profile” of connected instruments, together with any user-entered descriptive comments, is then securely saved in the system registry. Subsequent data transmissions to and from the instrument use this information to give the fastest possible communication. 

    Up to ten compatible instruments can be controlled independently or simultaneously, so that for example in a system measuring impedance one lock-in amplifier can measure the sample current while a second measures the voltage. Both instruments can be read via the control and the output readings combined to determine the impedance. 

    The package includes a full printed instruction manual, as well as on-screen help so that programming information is always easily available. In addition, sample applications in Visual Basic, Visual C++, Visual C#, LabVIEW, Excel and VBScript (HTML web page) are supplied. The VB, Visual C++ and Visual C# examples include a working executable as well as a full project workspace with all the corresponding source files. Similarly the LabVIEW, Excel and VBScript demonstration programs are complete with all source code information so that they can be easily edited by the user. 
  • Brochure and Manual +

  • Differentiated Specifications +

     Specifications  7270 7230 7280 7265  7225 
    Dual Reference,
    Dual Harmonics
    YES YES  YES to 20 kHz
    Option to 800 KHz
    or 2 MHz
    YES to 20 kHz NO
    Connectivity Ethernet,
    Frequency Range
    (X to 1 mHz)
    120 kHz
    optional 250 kHz
     250 kHz 2 MHz to 0.5 Hz 250 kHz  120 kHz  
    Dynamic Reserve   100 dB for 1 nV / √ Hz
    Types of References Internal, External
    with Virtual
    Internal, External 
    with Virtual
    Internal, External  Internal, External  Internal, External 
    Control Interface Computer Controlled  Computer Controlled,
    Full Front Panel
    Computer Controlled,
    Full Front Panel
     Computer Controlled, 
    Limited Front Panel
    Computer Controlled,
    Limited Front Panel
  • Detailed Specifications +

    Dual-phase DSP lock-in amplifier operating over a reference frequency range of 0.001 Hz to 250 kHz.

    Wide range of extended measuring modes and auxiliary inputs and outputs.

    User-upgradeable firmware.
    Measurements Modes
    The instrument can simultaneously show any four of these outputs on the front panel display:
    X In-phase
    Y Quadrature
    R Magnitude
    ø Phase Angle
    Harmonic nF, n≤ 65, 536
    Dual Harmonic
    Simultaneously measures the signal at
    two different harmonics F1 and F2of the
    reference frequency
    Dual Reference
    Simultaneously measures the signal at
    two different reference frequencies, F1
    F2 where F1 is the external and F2the
    internal reference
    Frequency Range for Dual Harmonic and Dual Reference Modes
    F1 and F2 ≤ 20 kHz
    Virtual Reference
    Locks to and detects a signal without a
    reference (100 Hz ≤ F ≤ 250 kHz)
    Measures noise in a given bandwidth
    centered at the reference frequency F
    Spectral Display
    Gives a visual indication of the spectral
    power distribution of the input signal in a
    user-selected frequency range lying
    between 1 Hz and 60 kHz. Note that
    although the display is calibrated in
    terms of frequency, it is not calibrated
    for amplitude. Hence it is only intended
    to assist in choosing the optimum
    reference frequency
    240 x 64 pixel cold fluorescent backlit
    LCD panel giving digital, analog bar-
    graph and graphical indication of
    measured signals. Menu system with
    dynamic key function allocation. On-
    screen context sensitive help
    Signal Channel
    Voltage Input

    A only, -B only or Differential (A-B)
    Full-scale Sensitivity 2 nV to 1 V in a 1-2-5 sequence
    Max. Dynamic Reserve > 100 dB
    FET Input
    Bipolar Input

    10 MΩ // 30 pF
    10 kΩ // 30 pF
    Maximum Safe Input 20 V pk-pk
    Voltage Noise
    FET Input
    Bipolar Input

    5 nV/√Hz @ 1 kHz
    2 nV/√Hz @ 1 khZ
    C.M.R.R. > 100 dB @ 1 kHz
    Frequency Response 0.001 Hz to 250 kHz
    Gain Accuracy ±0.2% typ
    Distortion -90 dB THD (60 dB AC gain, 1 khZ)
    Line Filter attenuates 50, 60, 100, 120 Hz
    Grounding BNC shields can be grounded or floated via 1 kΩ to ground
    Current Input
    Mode Low Noise or Wide Bandwidth
    Full-scale Sensitivity
    Low Noise
    Wide Bandwidth

    2fA to 10 nA in a 1-2-5 sequence
    2 fA to 1 µA in a 1-2-5 sequence
    Max. Dynamic Reserve > 100 dB
    Frequency Response (-3 dB)
    Low Noise
    Wide Bandwidth
    > 500 Hz
    ≥ 50 kHz
    Low Noise
    Wide Bandwidth

    < 2.5 kΩ ! 100 Hz
    <250 Ω @ 1 kHz
    Low Noise
    Wide Bandwidth

    13 fA/√Hz @ 500 Hz
    1.3 pA/√Hz @ 1 kHz
    Gain Accuracy ± 0.6% typ, midband
    Line Filter attenuates 50, 60, 100, 120 Hz
    Grounding BNC shield can be grounded or floated via 1 kΩ to ground-
    Reference Channel
    TTL input (rear panel)
    Frequency Range

    0.001 Hz to 250 kHz
    Analog Input (front panel)
    Sinusoidal input
    Frequency Range
    Squarewave input
    Frequency Range

    1 MΩ // 30 pF

    1.0 V rms*
    0.3 Hz to 250 kHz

    250 mV rms*
    2 Hz to 250 kHz
    *Note: Lower levels can be used with the analog input at the expense of increased phase errors
    Phase Set Resolution 0.001º increments
    Phase Noise at 100 ms TC, 12 dB/octave slope
    Internal Reference
    External Reference

    < 0.001º rms
    <0.01º rms @ 1 kHz
    Orthogonality 90º ±0.001º
    Acquistion Time
    Internal Reference

    instantaneous acquisition
    External Reference 2 cycles + 50 ms
    Reference Frequency Meter Resolution 1 ppm or 1 mHz, whichever is the greater
    Demodulator and Output Processing
    Output Zero Stability
    Digital Outputs
    Analog Outputs

    No zero drift on all settings
    No zero drift on all settings
    < 5 ppm/ºC
    Harmonic Rejection -90 dB
    Output Filters
    X, Y and R outputs only
    Time Constant

    Slope (roll-off)
    All outputs
    Time Constant

    10 µs to 640 µs in a binary sequence

    6 dB/octave

    5 ms to 100 ks in a 1-2-5 sequence
    6, 12, 18 and 24 dB/octave
    Synchronous Filter Available for F < 20 Hz
    Offset Auto and Manual on X and/or Y: ±300% full-scale
    Absolute Phase Measurement Accuracy ≤0.01º
    Setting Resolution
    1 mHz ≤ F ≤ 900 Hz
    F . 900 Hz
    Absolute Accuracy

    0.001 Hz to 250 kHz

    1 mHz
    4 mHz
    ± 50 ppm
    Distortion (THD) -80 dB @ 1 kHz and 100 mV rms
    Amplitude (rms)
    1µV to 4 mV
    4 mV to 500 mV
    500 mV to 2 V
    2 V to 5 V
    > 1 mV
    100 µV - 1 mV

    1 µV to 5 V rms
    125 µV
    500 µV
    1.25 mV

    ±0.3%, F ≤ 60 kHz, ±0.5%, F > 60 kHz
    ±1%,F ≤ 60 kHz, ±3%, F > 60 kHz
    50 ppm/ºC
    Output Impedance
    Amplitude Sweep
    Output Range
    Step Rate

    0.001 to 5.000 V rms
    20 Hz maximum (50 ms/step)
    Frequency Sweep
    Output Range
    Step Rate

    0.001 Hz to 250 kHz
    Linear or Logarithmic
    20 Hz maximum (50 ms/step)
    Auxiliary Inputs
    ADC 1 & 2
    Maximum input
    Input Impedance
    Smple Rate
    ADC 1 only
    ADC 1 and 2
    Trigger Mode
    Trigger Input

    ±10 V
    1 mV
    ±20 mV
    1 MΩ // 30 pF

    40 kHz max.
    17.8 kHz max.
    Internal, External or burst
    TTL compatible
    ADC 3
    Maximum input
    Input Impedance
    Sampling Time

    ±10 V
    12 to 20 bit, depending on sampling time
    1 MΩ // 30 pF
    10 ms to 2 s, variable
    Fast Outputs

    Update Rate

    X and Y or X and Mag
    ±2.5 V full-scale; linear to ±300% full-scale

    1 kΩ
    166 kHz
    Main Analog (CH1 and CH2) Outputs


    Update Rate

    X, Y, R, ø, Noise, Ratio, Log Ratio and User Equations 1 & 2.
    ±10.0 V full-scale; linear to ±120% full-scale

    1 kΩ
    200 Hz
    Signal Monitor

    ±10 V FS
    1 kΩ
    Auxiliary D/A Outputs 1, 2, 3 and 4
    Maximum Output
    Output Impedance

    ±10 V
    1 mV
    ±10 mV
    1 kΩ
    8-bit Digital Output Port
    8 TTL-compatible lines that can be independently
    set high or low to activate exteranl equipment
    Reference Output

    0 to 5 V rectangluar wave
    Power - Low Voltage ±15 V at 100 mA rear panel 5-pin 180º DIN connector for powering SIGNAL RECOVERY preamplifiers
    Data Storage Buffer

    Max Storage Rate

    From LIA
    From ADC1

    32k x 16-bit data points, may be organized as 1x32k, 2x16k, 3x10.6k, 4x8k, etc.

    up to 1000 16-bit values per second
    up to 40,000 16-bit values per second
    User Settings
    Up to 8 complete instrument settings can
    be saved or recalled from non-volatile
    RS232 and GPIB (IEEE-488). A second
    RS232 port is provided to allow "daisy-
    chain" connection and control of up to 16
    compatible instruments from a single
    RS232 computer port
    Power Requirements

    110/120/220/240 VAC
    50/60 Hz
    40 VA max
    With feet
    Without feet

    13¼" (350 mm)
    16½" (415 mm)

    4¼" (105 mm)
    3½" (90 mm)
    Weight 18 lb (8.1 kg)
  • Accessories +

    • Rack Mounts Kits

      Introduction content will come soon. Product page content:

      Keep Reading

  • Optional Software +