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Features
 Scitec Instruments Model 432 and Model 442 are OEM
analogue lock-in amplifiers with digital interfaces for controlling the boards.
Both the single phase Model 432 and dual phase Model 442 are suitable for
making amplitude and phase measurements but it is significantly easier with the
Model 442. These boards are controlled via a digital interface which can
connect to either an 8 bit bus of a µController or µProcessor or to
the parallel port of a PC.
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Single and dual phase versions |
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Differential or single-ended input |
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Sensitivities from 1 µV to 10 V for 1 V
output |
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High performance wide bandwidth input gain stage |
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Low pass filter output time constants from 100 µs to
30 s |
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1F and 2F reference signal operation |
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90° step and fine phase control |
 Model 432
A single phase lock-in amplifier with computer interface
for selection of input mode, sensitivity, low pass filter time constant, output
gain, offset and phase control (fine and course) of the reference signal.
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Sensitivity: 1 µV to 1 V in 1, 3, 10 steps for 1 V
output |
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Reference input: TTL/CMOS with mark/space of 1:10 to 10:1
(triggered from rising edge only). Sine, triangular, square waves etc with
amplitudes from 200 mV to 10 V. |
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Fine phase adjust: 0° to 150° in 256 steps. |
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Computer interface: 34 pin IDC connector can be connected to
PC parallel port |
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Power: -15 V, 0 V, +15 V dc at 50 mA per supply
rail. |
 Model 442
A dual phase lock-in amplifier with computer interface
for selection of input mode, sensitivity, low pass filter time constant, output
gain, offset and phase control (fine and course) of the reference signal. Can
be used in any of the following three modes:
Dual phase operation - one input signal with two
demodulators operating 90° apart providing both X and Y (or real and
imaginery) components of the input signal.
R calculation - on board circuitry provides the modulus
of the X and Y components.
Single channel 1F and 2F operation - one input signal
and two demodulators operating at 1x and 2x the reference frequency to measure
the first and second harmonics of the input signal.
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Sensitivity: 1 µV to 1 V in 1, 3, 10 steps for 1 V
output |
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Reference input: TTL/CMOS with mark/space of 1:10 to 10:1
(triggered from rising edge only). Sine, triangular, square waves etc with
amplitudes from 200 mV to 10 V. |
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Fine phase adjust: 0° to 150° in 256 steps. |
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Computer interface: 34 pin IDC connector can be connected to
PC parallel port |
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Power: -15 V, 0 V, +15 V dc at 50 mA per supply
rail. |
Please contact us for additional
information. |
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Specifications
Input Signal Channels
The input signal channel amplifies the input signal to a
level suitable for the demodulator(s). High performance, low-noise, broad-band
amplifiers are used throughout. The input circuits can accept differential or
single-ended inputs via the input SMB connectors. Options within the unit allow
the outer SMB contact or screen to act as a high impedance differential input
or allow it to be connected to ground for single-ended operation.
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Input: Differential or single ended voltage via SMB
socket |
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Input Gain: x0.1 to x330 in 1, 3.3, 10 steps |
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Input Impedance: 10¹² // 1 nF, dc coupled |
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Frequency: 10 Hz to 100 kHz |
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Maximum Inputs: ±10 V before saturation
occurs |
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Input Noise Voltage: Other lock-in amplifier manufacturers
give input noise values but without providing any definition of this
specification. Indeed there is no meaningful definition of this specification
in relation to lock-in amplifiers. As such, Scitec Instruments does not provide
noise values and other manufacturers data sheets are considered misleading.
Further details about input noise are available on request |
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Gain Accuracy: 1% |
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Gain Stability: 200ppm/°C |
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Dynamic Reserve: 0dB to 80dB |
Demodulator
The input stage drives high bandwidth demodulators to
recover the input signal.
Output
The demodulator outputs are passed through low pass
filters before being amplified for output.
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Output Gain: x1, x10, x100, x1000 |
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Low Pass Filter Time Constants: 100 µs to 30 s in 1,
3, 10 steps |
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Outputs - SMB connectors: +/-100 mV to +/-10 V full
scale |
Reference Channel
A single reference channel is used to generate the
signals that drive the demodulator(s). A fine phase shifting circuit allows the
reference signal to be phase shifted from 0° to 150° relative to the
signal input. A second circuit then produces signals that are phase shifted by
0°, 90°, 180° and 270° at both the reference frequency and
twice the reference frequency.
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Frequency: 10 Hz to 100 kHz |
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Trigger: Standard TTL, 95% mark/space ratio min. Rising edge
triggered. |
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Acquisition Time: 10 s max. |
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Phase Control: 90° steps + fine shift of 0° -
150° |
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Phase Drift: 0.1°/C |
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1F and 2F operation |
General
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Power connections are made via a 64 pin type C DIN41612
connector. Signal connections are not possible via this connector. |
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Mechanical: 100 x 160 mm |
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Temperature Range: 0 - 50°C |
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Warranty: 2 years from date of shipment |
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Phase Drift: 0.1°/C |
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1F and 2F operation |
Please contact us for additional
information. |
