Pendulum Instruments · Multi-Channel Rubidium Frequency Calibrator
CNT-104R
Four-channel rubidium frequency calibrator and analyzer with metrology-grade accuracy, replacing five conventional instruments in one box
CNT-104R folds several pieces of calibration-lab equipment into one chassis: 4-channel frequency analysis, a built-in rubidium timebase, and traceable calibration capability. One unit takes on work that otherwise splits across a reference source, a counter and comparison gear. Time resolution is better than 7 ps and frequency resolution 12 to 13 digits per second. For a lab building or expanding its time and frequency calibration capacity without spreading budget and rack space over five instruments, this is the most direct route. Before ordering, check whether your units under test need inputs above 400 MHz. If so, the optional RF channel extends to 24 GHz.
Overview
A calibration lab's equipment list usually accumulates year by year: first a counter, then a reference source, later comparison gear, until every measurement spans three instruments and you carry their combined uncertainty yourself. The value of CNT-104R is a shorter chain. The rubidium timebase sits inside the instrument and the four measurement channels reference it directly, with no transfer stage in between and therefore no extra uncertainty source. Four channels (A, B, D and E; C is the optional RF channel) handle several units under test at once, and with 12 to 13 digits per second of frequency resolution one run yields a statistically sufficient sample rather than a handful of readings. In practice it serves as the working standard for routine calibration, as the frequency acceptance instrument at the end of a production line, and as the R&D tool when several signals must be viewed relative to each other. The long-term stability of the rubidium reference also makes it usable in the field where no external reference is available.
Key specifications
| Measurement channels | 4 channels (A, B, D, E; optional channel C for RF) |
|---|---|
| Standard input frequency range | DC to 400 MHz |
| Optional RF input frequency range | Extends to 24 GHz (optional RF input module) |
| Time resolution | <7 ps |
| Frequency resolution | 12 to 13 digits/s |
| Gate time range | 50 ns to 1000 s (variable) |
| Maximum measurement rate | 20 M measurements/s (4 channels in parallel); fast block measurements up to 170 k/s |
| Internal memory | Up to 32 M samples |
| Reference oscillator | Built-in 10 MHz rubidium oscillator |
| Frequency calibration accuracy | Free run: better than 6×10⁻¹⁰ (24 h average, up to 1 year after calibration); 1×10⁻¹² (24 h average, with the optional GNSS module, Option 55) |
| Time calibration uncertainty | <10 ns rms to UTC (with the optional GNSS module) |
| Input impedance | 1 MΩ or 50 Ω (selectable) |
| Input connectors | Main inputs A/B/D/E: BNC; RF input C: 2.92 mm (SMA compatible) |
| Power supply | 100 to 240 VAC (±10%), 47 to 63 Hz, under 70 W |
| Operating temperature | 0°C to +50°C, relative humidity 5% to 75% |
| Storage temperature | -40°C to +71°C |
Features
The timebase is inside
A built-in rubidium oscillator feeds the measurement channels directly. No external reference to connect, and one less transfer uncertainty to budget for.
One unit in place of five
Frequency analysis, time interval, phase comparison and the reference source merge into one box, cutting rack space and yearly calibration cost together.
Four channels sampled together
Several units under test or several signals are finished in one measurement run, with no re-cabling between them.
Metrology-grade resolution
12 to 13 digits per second of frequency resolution and time resolution under 7 ps are enough to support a calibration lab's uncertainty budget.
Frequency range can grow
DC to 400 MHz as standard; the optional RF module extends coverage to 24 GHz for microwave units under test.
Usable in the field
The long-term stability of the rubidium timebase keeps it at rated performance where no external reference exists.
Typical applications
Metrology and calibration
Parallel calibration of several oscillators
Metrology labs and in-house calibration departments measure 4 oscillators or frequency sources at once against the built-in rubidium reference (1×10⁻¹² over a 24 h average with the GNSS option). One CNT-104R replaces 4 conventional counters plus a separate reference, shortening calibration cycles and lowering equipment cost.
Aerospace and defense
Frequency analysis of communication and navigation systems
When testing radios, radar and navigation equipment, aerospace and defense contractors use the modulation domain analysis (MDA) of CNT-104R to capture transient frequency changes in pulsed RF with time resolution better than 7 ps. It also works as a travelling clock for verifying site clocks outside the lab, independent of fixed GNSS infrastructure.
Telecom synchronization
5G and telecom network clock traceability verification
Telecom equipment makers and network sync engineers use CNT-104R to assess frequency stability and drift of GSM, 4G LTE and 5G base station clocks. With GNSS disciplining, time uncertainty is calibrated to 10 ns rms against UTC, supporting traceability requirements such as ITU-T G.8272.
Options and configuration
Tick the options you need. We compile the configuration into a list and carry it into the quote request form.
Standard equipment (included)
Hardware options
Software options
Downloads
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Also available for rent: CNT-104R is part of the Pendulum rental program, for project peaks, calibration backup and pre-purchase trials. Rental inquiry →