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SR620 Time Interval and Frequency Counter from SRS Stanford Research
Systems
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| SR620 Time Interval and Frequency Counter ( and SR625 with Rb Timebase ) |
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Full
brochure with detailed specifications
(455kB)
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SR625
version - Rubidium timebase, 2GHz pre-scaler - Full
brochure
(355kB)
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The SR620 Time Interval Counter performs virtually all the time and frequency measurements required in a laboratory or ATE environment. The instrument's high single-shot timing resolution, low jitter and outstanding flexibility make it the counter of choice for almost any application. SR620 Measurements The SR620 measures time interval, frequency, pulse-width, rise and fall time, period, phase and events. Time intervals are measured with 25 ps rms resolution, making the SR620 one of the highest resolution counters available. Frequency is measured from 0.001 Hz to 1.3 GHz, and a choice of gates ranging from 1 period to 500 seconds are provided. The SR620 delivers up to 11 digits of frequency resolution in a 1 second measurement. It's suitable for measurement applications ranging from short-term phase locked loop jitter, to long-term drift of atomic clocks. All measurement modes are supported by a wide variety of flexible arming and triggering options.
Histograms and Strip Charts Unlike conventional counters that only have numeric displays, the SR620 Frequency Counter provides live, graphical displays of measurement results. Graphical output of measurement data is available in three formats: a histogram showing the distribution of values within a set of measurements, a strip chart of mean values from successive measurements, or a strip chart of jitter (standard deviation or Allan variance) values from successive measurements. Up to 250 strip chart points, or histogram bins, can be displayed. Both histograms and strip charts can be displayed on any oscilloscope with an X-axis input (see the pictures above), or can be plotted on an HP-GL compatible plotter or dot-matrix printer. Convenient cursors allow you to read the value of any data point in the histogram or strip chart. Autoscale and zoom features make it simple to display all, or any portion, of the graphs. Complete Statistical Calculations The SR620 Time Interval / Frequency Counter can make measurements on a single-shot basis or calculate the statistics of a set of measurements. Sample sizes from one to one million can be selected. The SR620 will automatically calculate the mean, standard deviation or Allan variance, minimum and maximum for each set of measurements. Reference Output A precision, 1 kHz, 50 % duty cycle square wave is available at the front-panel REF output. The REF output can be used as a source of start or stop pulses for any of the SR620's measurement modes. For instance, the length of a cable connected between REF and the B input can be precisely determined by measuring the time delay between REF and B. Built-In DVMs and Analog Outputs Two rear-panel DVM inputs make measurements of DC voltages with 0.3 % accuracy (±20 VDC range). These values may be read via the interfaces or displayed directly on the front panel. Two rear-panel DAC outputs continuously provide voltages proportional to the mean and the jitter of the measurement sample. These 0 to 10 V outputs can drive strip chart recorders or can be set to provide fixed or scanned output voltages. Built-In Auto-Calibration A sophisticated, built-in auto-calibration routine nulls insertion delays between start and stop channels and compensates for the differential nonlinearites inherent in analog time-measurement circuitry. The auto-calibration routine takes about two minutes to perform and should be run every 1000 hours of operation. 10 MHz Reference The choice of timebase affects both the resolution and accuracy of measurements made with the SR620. SRS offers a choice of a standard timebase with an aging coefficient of 1 ´ 10-6/year, or an optional ovenized-oscillator timebase with only 5 ´ 10-10/day aging, and about an order of magnitude better short-term stability than the standard timebase. A rear-panel input lets you connect any external 5 MHz or 10 MHz source as a timebase. Computer Interfaces Standard GPIB (IEEE-488.2) and RS-232 interfaces allow remote control of the SR620 Frequency Counter. All instrument functions and configuration menu settings are accessible via the interfaces. A fast binary dump mode outputs up to 1400 measurements per second to a computer. A parallel printer port allows direct printing from the instrument. Standard IEEE-488.2 communications are supported, and plotter outputs are provided in HP-GL format making interfacing simple and easy. For convenient debugging, the last 256 characters transmitted over the interfaces can be viewed on the front panel. | |||
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| Timebase | |||
| Standard | Option 01 | ||
| Frequency | 10.000 MHz | 10.000 MHz | |
| Type | TCVCXO | Ovenized VCXO | |
| Aging | 1 ´ 10-6/yr | 5 ´ 10-10/day | |
| Allan variance (1 s) | 3 ´ 10-10 (typ.) | 1 ´ 10-11 | |
| Stability 0 to 50 °C | 1 ppm | <2 ´ 10-9 | |
| Settability | 0.01 ppm | 0.001 ppm | |
| External timebase | User may supply 5 or 10 MHz timebase. 1 volt nominal. | ||
| Time Interval, Width, Rise and Fall Times | |||
| Range | -1000 to +1000 s in +/-TIME mode; -1 ns to +1000 s in all other modes | ||
| Trigger rate | 0 to 100 MHz | ||
| Display LSD | 4 ps single sample, 1 ps with averaging | ||
| Resolution | |||
| Standard timebase | (((25 ps typ. [50 ps max.])2 + (0.2 ppb ´ Interval)2) / N)1/2 rms | ||
| Option 01 | (((25 ps typ. [50 ps max.])2 + (0.05 ppb ´ Interval)2) / N)1/2 rms, (N = sample size) | ||
| Error | <±(500 ps typ. [1 ns max.] + Timebase Error ´ Interval + Trigger Error) | ||
| Relative error | <±(50 ps typ. [100 ps max.] + Timebase Error x Interval) | ||
| Arming modes | +TIME (Stop is armed by Start) +TIME EXT (Ext arms Start) +TIME EXT HOFF (Leading EXT edge arms Start, trailing EXT edge arms Stop) ±TIME (Armed by Start/Stop pair) ±TIME CMPL (Armed by Stop/Start pair) ±TIME EXT (Armed by EXT input edge) EXT arming may be internally delayed or scanned with respect to the EXT input in variable steps. The step size may be set in a 1-2-5 sequence from 1 µs to 10 ms. The maximum delay is 50,000 steps. | ||
| Display | 16-digit fixed point with 1 ps LSD | ||
| Sample rate | N ´ (800 µs +
measured time interval) + calculation time (N=sample size) The calculation time occurs only after N measurements are completed and varies from zero (N=1, no graphics, binary) to 5 ms (N=1, no graphics) to 10 ms (display mean or standard deviation) to 60 ms (histogram). | ||
| Frequency | |||
| Range | 0.001 Hz to 300 MHz via comparator inputs. 40 MHz to 1.3 GHz via internal UHF prescalers. RATIO A/B range: 10-9 to 103 | ||
| Error | <±((100 ps typ. [350 ps max.])/Gate + Timebase Error ) ´ Frequency | ||
| Gates | External, 1 period, 1 µs to 500 s in 1-2-5 sequence. Gates may be externally triggered with no delay. Gates may be delayed relative to an EXT trigger. The delay from trigger is set from 1 to 50,000 gate widths. | ||
| Display | 16-digit fixed point with LSD = Freq ´ 4 ps/Gate. 1 µHz maximum resolution (1 nHz with ´1000 for frequencies <1 MHz) | ||
| Period | |||
| Range | 0 to 1000 s RATIO A/B range: 10-9 to 103 | ||
| Error | <±((100 ps typ [350 ps max])/Gate + Timebase Error) ´ Period | ||
| Gates | Same as frequency | ||
| Display | 16-digit fixed point with LSD = 1 ps (1 fs with ´1000 for periods <1 s) | ||
| Phase | |||
| Definition | Phase = 360 ´ (Tb - Ta) / Period A | ||
| Range | -180 to +180 degrees, 0 to 100 MHz | ||
| Resolution | (25 ps ´ Freq. ´ 360 + 0.001)° | ||
| Gate | 0.01 seconds (1 period min.) for period measurement and 1 sample for time interval measurement. Period may also be measured using externally triggered internal gates as in frequency mode. | ||
| Error | <±(1 ns ´ Freq. ´ 360 + 0.001)° | ||
| Counts | |||
| Range | 1012, RATIO A/B range: 10-9 to 103 | ||
| Count Rate | 0 to 300 MHz | ||
| Gates | Same as frequency | ||
| Display | 12 digits | ||
| Inputs | |||
| Bandwidth | 300 MHz, 1.2 ns rise time | ||
| Threshold | -5.00 to +5.00 VDC (10 mV resolution) | ||
| Accuracy | 15 mV + 0.5 % of setting | ||
| Sensitivity | See graph | ||
| Auto level | Threshold set between peak input excursions. (f >10 Hz, duty cycle >10-6) | ||
| Slope | Rising or falling edge | ||
| Impedance | (1 MW + 30 pf) or
50 W 50 W termination has SWR < 2.5:1 from 0 to 1.3 GHz | ||
| Coupling | AC or DC (Ext is always DC coupled) | ||
| Input noise | 350 µVrms (typ.) | ||
| Prescaler | See graph | ||
| Protection | 100 V, 50 W terminator is released if input exceeds ±5 Vp | ||
| REF Output | |||
| Frequency | 1.00 kHz (Accuracy same as timebase) | ||
| Rise/Fall | 2 ns | ||
| Amplitude | TTL: 0 to 4 V (2 V into 50 W) ECL: -1.8 to -0.8 V into 50 W | ||
| DVM Inputs | |||
| Full scale | ±1.999 or ±19.99 VDC | ||
| Type | Sample & hold with successive approximation converter | ||
| Impedance | 1 MW | ||
| Accuracy | 0.3 % of full scale | ||
| Speed | Approximately 5 ms | ||
| D/A Outputs | |||
| Full scale | ±10.00 VDC | ||
| Resolution | 5 mV | ||
| Impedance | <1 W | ||
| Default | Voltage proportional to mean and deviation | ||
| Accuracy | 0.3 % of full scale | ||
| Graphics | |||
| Scope | Two rear-panel outputs to drive x-y analog oscilloscope | ||
| Displays | Histograms and strip charts of mean and jitter | ||
| X-axis | -5 to +5 V for 10 division deflection | ||
| Y-axis | -4 to +4 V for 8 division deflection | ||
| Resolution | 250 (H) ´ 200 (V) pixels | ||
| Hardcopy | Centronics port for dot matrix printers. RS-232, IEEE-488.2 for HP-GL compatible plotters. | ||
| Interfaces | |||
| RS-232C | 300 to 19.2 kbaud. All instrument functions may be controlled. | ||
| GPIB | IEEE-488.2 interface. All instrument functions may be controlled. | ||
| Speed | Approximately 150 ASCII formatted responses per second. 1400 binary responses per second. | ||
| General | |||
| Operating | 0 °C to 50 °C | ||
| Power | 70 W, 100/120/220/240 VAC (+5 %, -10 %), 50/60 Hz | ||
| Dimensions | 14" ´ 3.5" ´ 14" (WHL) | ||
| Weight | 11 lbs. | ||
| Warranty | One year parts and labor on defects in materials and workmanship | ||
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Get More Information: Please contact our sales desk and ask for a data sheet along with a brochure covering other SRS products. Alternatively use the PDF link to download the data sheet, or use the Request Data button to ask for one to be sent to you. |
Discuss an Application
or Please contact our sales desk and ask to speak to one of our qualified sales engineers. They will be pleased to discuss the product and its use in your application. They can also arrange a visit to demonstrate the product. |
Place an Order Please contact our sales desk for quotations and current availability information. Use the Quote/Buy button at the top. |
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Thurlby Thandar Instruments
Limited |
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