IBM 7220 1.3 Key Specifications and Benefits

1-3

Chapter 1, INTRODUCTION

1.3 Key Specifications and Benefits

The EG&G Instruments Model 7220 represents the latest in DSP Lock-in Amplifier

technology at an affordable price, and offers:-

nFrequency range: 0.001 Hz to 120 kHz

nVoltage sensitivity: 20 nV to 1 V full-scale

nCurrent input mode sensitivities: 20 fA to 1 µA full-scale

20 fA to 10 nA full-scale

nLine frequency rejection filter

nDual phase demodulator with X-Y and R-θθ

θθ

θ outputs

nVery low phase noise of < 0.0001o rms

n5-digit output readings

nDirect Digital Synthesizer (DDS) oscillator with variable output amplitude

and frequency

nOscillator frequency sweep generator

nOutput time constant: 10 µs to 5 ks

n8-bit programmable digital output port for system control

nTwo external ADCs, two external DACs

nFull range of auto-modes

nStandard IEEE-488 and RS232 interfaces with RS232 daisy-chain

capability

nDual back-lit liquid crystal display (LCD) with variable contrast control

n32768 point curve storage buffer

Contents

Main FCC Notice Declaration of Conformity Table of Contents Table of Contents Chapter One, Introduction Chapter Two, Installation & Initial Checks Chapter Three, Technical Description Chapter Four, Front and Rear Panels Chapter Five, Front Panel Operation Chapter Six, Computer Operation Appendix A, Specifications Page Page Introduction Chapter 1 1.1 How to Use This Manual Chapter 1, INTRODUCTION 1.2 What is a Lock-in Amplifier? Chapter 1, INTRODUCTION 1.3 Key Specifications and Benefits Page Installation & Initial Checks Chapter 2 2.1 Installation 2.1.01 Introduction 2.1.02 Rack Mounting Page 2.2 Initial Checks 2.2.01 Introduction 2.2.02 Procedure Page Technical Description Chapter 3 3.1 Introduction 3.2 Principles of Operation 3.2.01 Block Diagram 3.2.02 Signal-Channel Inputs 3.2.03 Line Frequency Rejection Filter 3.2.04 AC Gain 3.2.05 Anti-Aliasing Filter 3.2.06 Main Analog to Digital Converter 3.2.07 Reference Channel DSP 3.2.08 Internal Oscillator 3.2.09 Demodulator DSP 3.2.10 Output Processor 3.2.11 Main Microprocessor 3.3 Accuracy 3.3.01 Absolute Accuracy Specifications 3.3.02 Relative Accuracy 3.4 Full-Scale Sensitivity and AC Gain Control 3.5 Dynamic Reserve 3.6 System Updates and Reference Frequency Changes 3.7 Reference Phase and Phase Shifter 3.8 Output Channel Filters 3.8.01 Slope 3.8.02 Time Constants and Synchronization 3.8.03 Output Offset and Expand 3.9 Use of Magnitude and Signal Phase Outputs Page 3.10 Noise Measurements 3.11 Power-up Defaults 3.12 Auto Functions 3.12.01 Introduction 3.12.02 Auto-Sensitivity 3.12.03 Auto-Phase 3.12.04 Auto-Offset 3.12.05 Auto-Measure 3.12.06 Default Setting Front and Rear Panels Chapter 4 4.1 Front Panel 4.1.01 A and B/I Signal Input Connectors 4.1.02 OSC OUT Connector 4.1.03 REF IN Connector 4.1.04 Left-hand LCD Display Panel Page 4.1.05 MENU Key 4.1.06 90 Key 4.1.07 SET Key 4.1.08 Right-hand LCD Display Panel 4.2 Rear Panel 4.2.01 Line Power Switch 4.2.02 Line Power Input Assembly Page Page Front Panel Operation Chapter 5 5.1 Introduction 5.2 Setup Menu Mode 5.2.01 Input Setup Menu Page 5.2.02 Reference Setup Menu ON OFF 5.2.03 Output Setup Menu Expand Page PHASE1 PHASE2 NOISE RATIO 5.2.04 Control Options Menu Linefilt AC Gain Page 5.2.05 Miscellaneous Options Menu 5.2.06 RS232 Setup 1 Menu 5.2.07 RS232 Setup 2 Menu 5.2.08 RS232 Setup 3 Menu Address Information only 5.2.09 GPIB Setup 1 Menu 5.2.10 GPIB Setup 2 Menu SRQ Mask Test echo 5.2.11 Digital Outputs Setup Menu Decimal 5.2.12 Control Setup Menu Default Setting Sample rate 5.3 Auto Functions Menu AUTO SEN AUTO PHASE AUTO OFFSET AUTO MEASURE 5.4 Main Display Mode - Left-hand LCD Page Page Page Page Page 5.5 Main Display Mode - Right-hand LCD Page Page Page Page Page Page Page Page 5.6 Typical Lock-in Amplifier Experiment Page Computer Operation Chapter 6 6.1 Introduction 6.2 Capabilities 6.2.01 General 6.3 RS232 and GPIB Operation 6.3.01 Introduction 6.3.02 RS232 Interface - General Features 6.3.03 Choice of Baud Rate 6.3.04 Choice of Number of Data Bits 6.3.05 Choice of Parity Check Option 6.3.06 Auxiliary RS232 Interface 6.3.07 GPIB Interface - General Features 6.3.08 Handshaking and Echoes 6.3.09 Terminators 6.3.10 Command Format 6.3.11 Delimiters 6.3.12 Compound Commands 6.3.13 Status Byte, Prompts and Overload Byte Page 6.3.14 Service Requests 6.4 Command Descriptions 6.4.01 Signal Channel Page Page 6.4.02 Reference Channel 6.4.03 Signal Channel Output Filters 6.4.04 Signal Channel Output Amplifiers 6.4.05 Instrument Outputs Page Page 6.4.06 Internal Oscillator 6.4.07 Auxiliary Outputs 6.4.08 Auxiliary Inputs Page 6.4.09 Output Data Curve Buffer Page Page Page 6.4.10 Computer Interfaces (RS232 and GPIB) Page 6.4.11 Instrument Identification 6.4.12 Front Panel 6.4.13 Default Setting 6.5 Programming Examples 6.5.01 Introduction 6.5.02 Basic Signal Recovery 6.5.03 Frequency Response Measurement 6.5.04 X and Y Output Curve Storage Measurement 6.5.05 Transient Recorder 6.5.06 Frequency Response Measurement using Curve Storage and Frequency Sweep Page Specifications Appendix A Measurement Modes Displays Signal Channel Reference Channel Demodulator and Output Processing Oscillator Auxiliary Inputs Outputs Data Storage Interfaces Power Requirements General Pinouts Appendix B B.1 RS232 Connector Pinout B.2 Preamplifier Power Connector Pinout Appendix B, PINOUTS B.3 Digital Output Port Connector Demonstration Programs Appendix C C.1 Simple Terminal Emulator C.2 RS232 Control Program with Handshakes Page C.3 GPIB User Interface Program Page Cable Diagrams Appendix D D.1 RS232 Cable Diagrams Page Alphabetical Listing of Commands Appendix E Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Default Settings Appendix F Default Setting Function Appendix F, DEFAULT SETTINGS Index Index Index-1 Index-2 Index-3 Index-4 Index-5 Page WARRANTY SHOULD YOUR EQUIPMENT REQUIRE SERVICE