The Stanford Research Systems SR620 is a universal time interval and frequency counter offering 25 ps single-shot timing resolution and frequency measurements up to 1.3 GHz. Designed for laboratory and ATE environments, it features built-in statistical analysis, Allan variance calculations, and live graphical outputs to external oscilloscopes for histograms and strip charts.
Specifications
General
| Parameter | Value |
|---|---|
| Interfaces | GPIB, RS-232 |
| Display | 16-digit alphanumeric LED |
Physical
| Parameter | Value |
|---|---|
| Power Supply | 100 / 120 / 220 / 240 VAC, 50/60 Hz, 50 W |
| Operating Temperature | 0 to +50 |
| Dimensions (W×H×D) | 356 x 89 x 356 |
| Weight | 4.5 |
Measurement Modes
| Parameter | Value |
|---|---|
| Available Measurements | Time interval, frequency, pulse-width, rise and fall time, period, phase, events |
Time Interval Specifications
| Parameter | Value |
|---|---|
| Single-Shot Resolution | 25 ps rms |
Frequency and Period Specifications
| Parameter | Value |
|---|---|
| Frequency Range | 0.001 Hz to 1.3 GHz |
| Frequency Resolution | Up to 11 digits (1 s gate) |
Phase Specifications
| Parameter | Value |
|---|---|
| Phase Resolution | 0.001° |
Timebase / Reference Oscillator
| Parameter | Value |
|---|---|
| Standard Oscillator Aging Rate | 1 × 10^-6 / year |
| Optional Ovenized Oscillator Aging Rate | 5 × 10^-10 / day |
Statistical and Math Functions
| Parameter | Value |
|---|---|
| Sample Size Range | 1 to 1,000,000 |
| Calculated Statistics | Mean, standard deviation, Allan variance, minimum, maximum |
| Histogram Generation | Up to 250 bins |
| Strip Chart Display | Mean or jitter (standard deviation / Allan variance), up to 250 points |
Display Characteristics
| Parameter | Value |
|---|---|
| Graphical Output | Via X-Y scope inputs or HP-GL compatible plotter/printer |
Auxiliary Outputs
| Parameter | Value |
|---|---|
| Internal Reference Output | 1 kHz, 50% duty cycle square wave |
Auxiliary Inputs
| Parameter | Value |
|---|---|
| DVM Inputs | 2 rear-panel channels |
| DVM Input Voltage Range | ±20 VDC |
| DVM Input Accuracy | 0.3% |
Calibration
| Parameter | Value |
|---|---|
| Auto-Calibration Duration | ~2 minutes |
Measurement Ranges
| Parameter | Value |
|---|---|
| Time Interval Range | -1000 s to +1000 s |
| Phase Measurement Range | -180° to +180° |
Inputs A & B
| Parameter | Value |
|---|---|
| Input Impedance (Inputs A & B) | 50 Ω or 1 MΩ |
| Input Coupling (Inputs A & B) | AC or DC |
| Trigger Level Range | ±5.00 V |
| Trigger Level Resolution | 10 mV |
| Input Bandwidth | 300 MHz |
| Input Sensitivity | 50 mVrms |
| Typical Input Noise | 350 µVrms |
Reference / Timebase
| Parameter | Value |
|---|---|
| Timebase Frequency | 10.000 MHz |
Outputs
| Parameter | Value |
|---|---|
| Internal Reference Output Level | 1 Vpp into 50 Ω |
| Analog Outputs (D/A) Channels | Two rear-panel outputs (X-axis, Y-axis) |
DVM Inputs
| Parameter | Value |
|---|---|
| DVM Input Impedance | 1 MΩ |
Performance
| Parameter | Value |
|---|---|
| Internal Time Jitter | 25 ps rms (typical) |
Inputs & Outputs
| Parameter | Value |
|---|---|
| External Arming Input | TTL level |
Power
| Parameter | Value |
|---|---|
| Power Consumption | 50 W |
Applications
Laboratory, ATE, Atomic clock drift measurement, PLL jitter measurement