Overview
The SIGNAL RECOVERY model 7225 offers a cost-effective solution to the researcher needing the performance provided by DSP demodulation but not requiring the additional features or higher operating frequencies of the models 7280 and 7265.
The instrument performs all of the normal measurements of a dual phase lock-in amplifier, 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 model 7225 is extremely easy to use. All 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 applicationssoftware, DemoAcquire, are available for download from our website at www.signalrecovery.com
- 1m Hz to 120 kHz Operation
- Direct digital demodulation with down-conversion
- 10 µs to 100 ks output time Constants
- Synchronous oscillator output for input offset reduction
- Harmonic measurements to 32f
- Low Profile (IRU)
- Chopped light measurements
- AC bridge measurements
- Audio studies
- AC impedance studies
- Vibration studies
- Thermal wave detection
The SIGNAL RECOVERY model 7225 offers a cost-effective solution to the researcher needing the performance provided by DSP demodulation but not requiring the additional features or higher operating frequencies of the models 7280 and 7265
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 |
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