Overview
The model 7230 is a new concept in general-purpose DSP lock-in amplifiers. It offers the excellent signal recovery performance that users expect from our instruments but at a lower price than many competitive models. We’ve achieved this improvement in price/performance ratio by replacing traditional control buttons and display with easy-to-use control panels that can be operated from any computer via your favorite browser. No longer do you need to be in front of the instrument to operate it – now you can set up your experiment in the lab but return to the office while it runs, monitoring what is happening via your computer. And if you need to make a change to a setting then it’s as easy as clicking a button on a web page.
You can use any web compatible device to operate the model 7230, ranging from a simple netbook to the most powerful development machine, from an Android smartphone to the latest iPad. No special software is needed, since the panels work directly through the device’s browser. All that is necessary is that the computer and instrument be connected to the same Ethernet network.
The instrument is also much more compact than traditional designs, making it easier to accommodate in crowded laboratories, and as it does not include any cooling fans it is completely silent, which is especially useful for acoustic research.
It is normally configured for operation over a frequency range extending from 1 mHz to 120 kHz. However, for a small extra charge it can also be delivered, or upgraded via a firmware update pack, to allow operation at frequencies of up to 250 kHz.
Versatility
In common with other models in our range the 7230 offers much more than just dual phase lock-in detection at the reference frequency of an applied signal. It includes 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, and tandem demodulation. It also includes virtual reference mode, allowing reference-free measurement of suitable signals.
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. The maximum rate at which data can be stored to the internal curve buffer is 1 μs per point, allowing direct capture of instrument outputs when using these short time constants. The buffer length of 100,000 sets of points gives a recording time of 100 ms at the fastest sampling rate.
Remote Control
The built-in web control pages allow full operation via the Ethernet interface, which with the USB and RS232 connections, can also be used to operate the instrument from our comprehensive software package, Acquire, from our ActiveX control and toolkit(SRInstComms), or using the free LabVIEW driver.
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In summary, the Model 7230 offers a very cost-effective solution to users who need a lock-in amplifier suitable for straightforward applications but with the versatility to also be used in complex experiments.
- 1 mHz to 120 kHz (250 kHz with 7230/99 option) operating frequency range
- 1.0 MHz main ADC sampling rate
- 10 µs to 100 ks output filter time constants
- Dual Reference, Dual Harmonic and Virtual Reference operating Modes
- Internal data buffer for recording instrument outputs at rates down to 1 µs per point
- Ethernet, USB, and RS232 computer Interfaces
- Free LabVIEW driver
The model 7230 is a new concept in general-purpose DSP lock-in amplifiers.
Specifications
Signal Channel | |
Voltage Input | |
Modes | A only, -B only or Differential (A-B) |
Frequency Response | 1 mHz < F < 120 or 250 kHz* |
Full-scale Sensitivity | 10 nV to 1 V in a 1-2-5 sequence (e.g. 10 nV, 20 nV, 50 nV, 100 nV, etc.) |
Impedance – FET input | 10 MΩ // 25 pF, AC or DC coupled |
Impedance – Bipolar input | 10 kΩ // 25 pF, input must be DC coupled |
Max safe input | ±12.0 V |
Voltage Noise – FET input | 5 nV/√Hz @ 1 kHz |
Voltage Noise – Bipolar input | 2 nV/√Hz @ 1 kHz |
C.M.R.R. | > 100 dB @ 1 kHz degrading by no more than 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 | 10 fA to 10 nA in a 1-2-5 sequence |
Wide Bandwidth | 10 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 |
Impedance | |
Low Noise | < 2.5 kΩ @ 100 Hz |
Wide Bandwidth | < 250 Ω @ 1 kHz |
Noise | |
Low Noise | 13 fA/√Hz @ 500 Hz |
Wide Bandwidth | 130 fA/√Hz @ 1 kHz |
Gain Accuracy | ±2.0% typ, midband |
Either Input Mode | |
Line Filter | Filter can be set to attenuate 50/60 Hz, 100/120 Hz, or both frequency bands |
Max. Dynamic Reserve | > 100 dB |
Grounding | BNC shield can be grounded or floated via 1 kΩ to ground |
Signal Molnitor Amplitude | ±1 V FS. This is the signal after preamplification and filtering, but before transmission over the optical link |
Output Impedance | 1 kΩ |
Reference Channel | |
Reference Input | |
TTL input setting | |
Freq. Range | 1 mHz to 120 or 250 kHz* |
Analog input setting | |
Impedance | 1 MΩ // 30 pF |
Sinusoidal Level | 1.0 V rms* |
Frequency Range | 0.5 Hz to 250 kHz* |
Squarewave Input Level | 250 mV rms |
Frequency Range | 2 Hz to 120 or 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 acquisition |
External Reference | 2 cycles + 1 s |
Reference Frequency Meter Resolution | 4 ppm or 1 mHz, whichever is the greater |
Demodulator and Output Processing | |
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 |
Reference Monitor | Rear panel TRIG OUT connector can be configured to generate TTL signal at current reference frequency, internal or external |
Oscillator – General | |
Frequency | |
Range | 1 mHz to 120 or 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 |
Sweep | |
Frequency Sweep | |
Output Range | 1 mHz to 120 or 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 | |
Amplitude | |
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 |
General | |
Power Requirements | Via external model PS0110 universal power supply |
Voltage | 100 – 240 VAC |
Frequency | 47 – 63 Hz |
Power | 40 VA max |
Dimensions | |
Width | Width 15½" (390 mm) |
Depth | Depth 10" (250 mm) |
Height | |
With feet | With feet 3" (75 mm) |
Without feet | Without feet 2½" (64 mm) |
Weight | Weight 6.6 lb (3.0 kg) |
Options | |
Model 7230/99 | Increases upper reference frequency limit from 120 kHz to 250 kHz. Can be installed by firmware upgrade. |
Preliminary specifications subject to change without notice |