MODEL SR830

1 MODEL SR830 . DSP Lock-In Amplifier 1290-D Reamwood Avenue Sunnyvale, California 94089. Phone: (408) 744-9040 Fax: (408) 744-9049. email: Copyright 1993, 2011 by SRS, Inc. All Rights Reserved. Revision (10/2011). TABLE OF CONTENTS. GENERAL INFORMATION REAR PANEL. Safety and Preparation for Use 1-3 Power Entry Module 4-27. Specifications 1-5 IEEE-488 Connector 4-27. Abridged Command List 1-7 RS232 Connector 4-27. Aux Inputs (A/D Inputs) 4-27. GETTING STARTED Aux Outputs (D/A Outputs) 4-27. X and Y Outputs 4-27. Your First Measurements 2-1. Signal Monitor output 4-28. The Basic Lock-in 2-3. Trigger input 4-28. X, Y, R and q 2-7. TTL Sync output 4-28. Outputs, Offsets and Expands 2-9. Preamp Connector 4-28. Storing and Recalling Setups 2-13. Using SRS Preamps 4-29. Aux Outputs and Inputs 2-15. SR830 BASICS PROGRAMMING. GPIB Communications 5-1.

2 What is a Lock-in Amplifier? 3-1. RS232 Communications 5-1. What Does a Lock-in Measure? 3-3. Status Indicators and Queues 5-1. The SR830 Functional Diagram 3-5. Command Syntax 5-1. Reference Channel 3-7. Interface Ready and Status 5-2. Phase Sensitive Detectors 3-9. GET (Group Execute Trigger) 5-2. Time Constants and DC Gain 3-11. DC Outputs and Scaling 3-13. Dynamic Reserve 3-15 DETAILED COMMAND LIST 5-3. Signal input Amplifier and Filters 3-17 Reference and Phase 5-4. input Connections 3-19 input and Filter 5-5. Intrinsic (Random) Noise Sources 3-21 Gain and Time Constant 5-6. External Noise Sources 3-23 Display and output 5-8. Noise Measurements 3-25 Aux input and output 5-9. Setup 5-10. Auto Functions 5-11. OPERATION Data Storage 5-12. Power On/Off and Power On Tests 4-1 Data Transfer 5-15. Reset 4-1 Interface 5-19.

3 [Keys] 4-1 Status Reporting 5-20. Spin Knob 4-1. Front Panel BNC Connectors 4-2 STATUS BYTE DEFINITIONS. Key Click On/Off 4-2 Serial Poll Status Byte 5-21. Front Panel Display Test 4-2 Service Requests 5-22. Display Off Operation 4-2 Standard Event Status Byte 5-22. Keypad Test 4-3 LIA Status Byte 5-23. Standard Settings 4-4 Error Status Byte 5-23. PROGRAM EXAMPLES. FRONT PANEL Microsoft C, Nationall Instr GPIB 5-25. Signal input and Filters 4-5. Sensitivity, Reserve, Time USING SR530 PROGRAMS 5-31. Constants 4-7. CH1 Display and output 4-12. CH2 Display and output 4-15 TESTING. Reference 4-18 Introduction 6-1. Auto Functions 4-21 Preset 6-1. Setup 4-23 Serial Number 6-1. Interface 4-24 Firmware Revision 6-1. Warning Messages 4-26 Test Record 6-1. If A Test Fails 6-1. Necessary Equipment 6-1. 1-1. TABLE OF CONTENTS. Front Panel Display Test 6-2.

4 Keypad Test 6-2. PERFORMANCE TESTS. Self Tests 6-3. DC Offset 6-5. Common Mode Rejection 6-7. Amplitude Accuracy and Flatness 6-9. Amplitude Linearity 6-11. Frequency Accuracy 6-13. Phase Accuracy 6-15. Sine output Amplitude 6-17. DC Outputs and Inputs 6-19. input Noise 6-21. Performance Test Record 6-23. CIRCUITRY. Circuit Boards 7-1. CPU and Power Supply Board 7-3. DSP Logic Board 7-5. Analog input Board 7-7. PARTS LISTS. DSP Logic Board 7-9. Analog input Board 7-16. CPU and Power Supply Board 7-22. Front Panel Display Boards 7-26. Miscellaneous 7-33. SCHEMATIC DIAGRAMS. CPU and Power Supply Board Display Board Keypad Board DSP Logic Board Analog input Board 1-2. SAFETY AND PREPARATION FOR USE. WARNING. Dangerous voltages, capable of causing injury or death, are present in this instrument. Use extreme caution whenever the instrument covers are removed.

5 Do not remove the covers while the unit is plugged into a live outlet. CAUTION SERVICE. This instrument may be damaged if operated Do not attempt to service or adjust this instrument with the LINE VOLTAGE SELECTOR set for the unless another person, capable of providing first aid wrong AC line voltage or if the wrong fuse is or resuscitation, is present. installed. Do not install substitute parts or perform any LINE VOLTAGE SELECTION unauthorized modifications to this instrument. Contact the factory for instructions on how to return The SR830 operates from a 100V, 120V, 220V, the instrument for authorized service and or 240V nominal AC power source having a line adjustment. frequency of 50 or 60 Hz. Before connecting the power cord to a power source, verify that the FURNISHED Accessories LINE VOLTAGE SELECTOR card, located in the rear panel fuse holder, is set so that the correct - Power Cord AC input voltage value is visible.

6 - Operating Manual Conversion to other AC input voltages requires a ENVIRONMENTAL CONDITIONS. change in the fuse holder voltage card position and fuse value. Disconnect the power cord, open OPERATING. the fuse holder cover door and rotate the fuse- Temperature: +10 C to + 40 C. pull lever to remove the fuse. Remove the small (Specifications apply over + 18 C to +28 C). printed circuit board and select the operating Relative Humidity: <90 % Non-condensing voltage by orienting the printed circuit board so that the desired voltage is visible when pushed NON-OPERATING. firmly into its slot. Rotate the fuse-pull lever back Temperature: -25 C to 65 C. into its normal position and insert the correct Humidity: <95 % Non-condensing fuse into the fuse holder. WARNING REGARDING USE WITH. LINE FUSE PHOTOMULTIPLIERS AND OTHER DETECTORS.

7 Verify that the correct line fuse is installed before The front end amplifier of this instrument is easily connecting the line cord. For 100V/120V, use a 1 damaged if a photomultiplier is used improperly with Amp fuse and for 220V/240V, use a 1/2 Amp the amplifier. When left completely unterminated, a fuse. cable connected to a PMT can charge to several hundred volts in a relatively short time. If this cable is LINE CORD connected to the inputs of the SR830 the stored charge may damage the front-end op amps. To The SR830 has a detachable, three-wire power avoid this problem, always discharge the cable and cord for connection to the power source and to a connect the PMT output to the SR830 input before protective ground. The exposed metal parts of turning the PMT on. the instrument are connected to the outlet ground to protect against electrical shock.

8 Always use an outlet which has a properly connected protective ground. 1-3. Symbols you may Find on SRS Products Symbol Description Alternating current Caution - risk of electric shock Frame or chassis terminal Caution - refer to accompanying documents Earth (ground) terminal Battery Fuse On (supply). Off (supply). 1-4. SR830 DSP LOCK-IN AMPLIFIER. SPECIFICATIONS. SIGNAL CHANNEL. Voltage Inputs Single-ended (A) or differential (A-B). Current input 106 or 10 8 Volts/Amp. Full Scale Sensitivity 2 nV to 1 V in a 1-2-5-10 sequence (expand off). input Impedance Voltage: 10 M +25 pF, AC or DC coupled. Current: 1 k to virtual ground. Gain Accuracy 1% from 20 C to 30 C (notch filters off), % Typical. input Noise 6 nV/ Hz at 1 kHz (typical). Signal Filters 60 (50) Hz and 120(100) Hz notch filters (Q=4). CMRR 100 dB to10 kHz (DC Coupled), decreasing by 6db/octave above 10 kHz Dynamic Reserve Greater than 100 dB (with no signal filters).

9 Harmonic Distortion -80 dB. REFERENCE CHANNEL. Frequency Range 1 mHz to 102 kHz Reference input TTL (rising or falling edge) or Sine. Sine input is1 M , AC coupled (>1 Hz). 400 mV pk-pk minimum signal. Phase Resolution . Absolute Phase Error <1 . Relative Phase Error < . Orthogonality 90 . Phase Noise External synthesized reference: rms at 1 kHz, 100 ms, 12 dB/oct. Internal reference: crystal synthesized, < rms at 1 kHz. Phase Drift < / C below 10 kHz < / C to 100 kHz Harmonic Detect Detect at Nxf where N<19999 and Nxf<102 kHz. Acquisition Time (2 cycles + 5 ms) or 40 ms, whichever is greater. DEMODULATOR. Zero Stability Digital displays have no zero drift on all dynamic reserves. Analog outputs: <5 ppm/ C for all dynamic reserves. Time Constants 10 s to 30 s (reference > 200 Hz). 6, 12, 18, 24 dB/oct rolloff. up to 30000 s (reference < 200 Hz).

10 6, 12, 18, 24 dB/oct rolloff. Synchronous filtering available below 200 Hz. Harmonic Rejection -80 dB. INTERNAL OSCILLATOR. Frequency 1 mHz to 102 kHz. Frequency Accuracy 25 ppm + 30 Hz Frequency Resolution 4 1/2 digits or mHz, whichever is greater. Distortion f<10 kHz, below -80 dBc. f>10 kHz, below -70 Vrms amplitude. output Impedance 50 . Amplitude 4 mVrms to 5 Vrms (into a high impedance load) with 2 mV resolution. (2 mVrms to Vrms into 50 load). Amplitude Accuracy 1%. Amplitude Stability 50 ppm/ C. Outputs Sine output on front panel. TTL sync output on rear panel. When using an external reference, both outputs are phase locked to the external reference. 1-5. SR830 DSP Lock-In Amplifier DISPLAYS. Channel 1 4 1/2 digit LED display with 40 segment LED bar graph. X, R, X Noise, Aux input 1 or 2. The display can also be any of these quantities divided by Aux input 1 or 2.