Circuit Description

 

Introduction

34

Signal Amplifier

34

Current Amplifier

34

Notch Filters

34

Bandpass Filter

34

Reference Oscillator

35

PSD, LP Filters and DC Amplifier

35

Analog Output

36

A/D's

36

D/A's

36

Expand

36

Front Panel

36

Microprocessor Control

36

RS232 Interface

37

GPIB Interface

37

Power Supplies

37

Internal Oscillator

37

Calibration and Repair

 

Introduction

38

Multiplier Adjustments

38

Amplifier and Filter Adjustments

38

CMRR Adjustment

38

Line Notch Filter Adjustment

39

2xLine Notch Filter Adjustment

39

Repairing Damaged Front-End

39

Appendix A: Noise Sources and Cures

 

Johnson Noise

40

'1/f' Noise

40

Noise Spectrum

40

Capacitive Coupling

41

Inductive Coupling

41

Ground Loops

42

Microphonics

42

Thermocouple Effect

42

Appendix B: RS232

 

Simplest Case Using the RS232

43

Using Control Lines

43

Baud Rates

43

Stop Bits

44

Parity

44

Voltage Levels

44

'Eavesdropping'

44

Appendix C: GPIB

 

Introduction to the GPIB

45

Bus Description

45

Appendix D: Program Examples

 

Program Description

46

IBM PC, Microsoft Basic, via RS232

46

IBM PC, Microsoft Fortran, via RS232

47

IBM PC, Microsoft C, via RS232

49

ii

IBM PC, Microsoft Basic, via GPIB

51

HP-85, HP Basic, via HPIB

53

Documentation

 

Parts List, Oscillator Board

55

Parts List, Main Board

56

Parts List, Front Panel Board

70

Parts List, Quad Board

73

Parts List, Miscellaneous

77

Schematic Diagrams

79

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SRS Labs Lock-In Amplifier, SR530 manual Appendix C Gpib

SR530, Lock-In Amplifier specifications

The SRS Labs Lock-In Amplifier, model SR530, is a powerful tool designed for high-precision measurements in the realm of scientific research and industrial applications. This state-of-the-art instrument excels in extracting small signals from noisy environments, making it an invaluable asset for experiments in fields such as physics, engineering, and materials science.

One of the main features of the SR530 is its ability to perform synchronous detection, which is key to improving signal-to-noise ratios. By utilizing a reference signal, the device correlates the incoming signal with the reference to effectively filter out noise, allowing for the accurate measurement of weak signals that might otherwise be obscured. This process of phase-sensitive detection is fundamental to the operation of the Lock-In Amplifier.

The SR530 offers a wide frequency range, covering from 0.1 Hz to 100 kHz. This broad frequency response allows it to handle a diverse array of signals, making it suitable for various applications including optical detection, capacitance measurements, and in many cases, voltammetry. The device is also equipped with multiple inputs and outputs, facilitating the integration with other laboratory equipment and enabling complex experimental setups.

Precision is further enhanced with its adjustable time constant, which allows users to optimize the response time based on experimental needs. The user can choose time constants from 10 microseconds to 10 seconds, accommodating fast dynamic measurements as well as those requiring stability over longer durations.

Another remarkable characteristic of the SR530 is its digital processing capabilities. The device features a highly accurate digital voltage measurement system, minimizing drift and ensuring long-term stability. Additionally, the use of microprocessors enhances data handling and allows for features such as programmable settings, facilitating automated measurements.

Moreover, the SR530 includes a range of output options, including analog outputs, which can be used for direct signal processing, as well as digital interfaces for integration with computers. This ensures that users can not only capture high-fidelity data but also analyze and display it efficiently.

In conclusion, the SRS Labs SR530 Lock-In Amplifier stands out due to its sophisticated technology, versatile features, and robust performance. Its precision, flexibility, and ease of use make it an ideal choice for researchers and engineers looking to unlock the potential of weak signal measurement in complex environments.