Frequency Standards

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Pendulum GPS-12R Frequency Standard

GPS-12R/HS & GPS12RG Portable GPS Frequency Standard

Accuracy, High-Stability and Performance

The GPS-12R/HS frequency standard offers traceable Cesium-like stability at a very attractive price. Synchronized to the GPS satellite system, the GPS-12R/HS provides both short and long–term time and frequency stability, assuring precision and accuracy.

  • GPS-disciplined Rubidium clock
  • Internal battery option for transportation and mains-free field use
  • Two switchable 1.544 MHz (T1) or 2.048 MHz (E1) front-panel output
  • One switchable 1 PPS or 10 MHz front-panel output
  • Eight optional frequency outputs: 1, 5 & 10 MHz
  • User friendly front panel operation, selectable for six language
  • Use of both GLONASS and GPS gives better signal coverage (GPS-12RG)


  • GPS-12R/HS - GPS-controlled high-stability Rubidium frequency reference giving near-Cesium stability with optimum phase performance

NOTE: The GPS-12R/HS is now offered at the same price as the previous base model GPS-12R and has the additional features:

  • Higher stability oscillator
  • Additional 3 x 10 MHz & 1 x 5 MHz low-noise sine outputs
  • Optional provision for DC operation (with option 78/HS)
  • GPS-12RG – Glonass/GPS-controlled High-stability Rubidium reference


GPS-12R/HS Pendulum_datasheet_button


Pendulum GPS-89 Frequency Standard

GPS-88/89 GPS-based Frequency Standard

Traceable Accurate Frequency Standards

The GPS-controlled frequency standards are especially suited for use in calibration departments, providing continuous traceability with no need for external calibration. The stability/24h is excellent; one part in a trillion.

Long-term frequency stability is provided from the built-in Cesium-controlled standards in the GPS-satellite. Very high short-term stability comes from the built-in oven controlled crystal oscillator found in the GPS-88; or the built-in Rubidium atomic clock installed in GPS-89, as its local oscillator.

  • GPS-controlled frequency standard
  • Choice of Rubidium or ovenized crystal oscillator
  • Traceable internal calibration system approved by Swedish National Testing and Research Institute 
  • Remote monitoring via Ethernet interface
  • No doubt-about-accuracy via display of frequency offset
  • Five standard frequency outputs; 4x10 and 1x5 MHz; Five more optional outputs



Pendulum 6688 Frequency Standard


6688/6689 Frequency Standard

Ideal Reference for Multiple Testers

These Pendulum frequency standards suit the highest demands for stability. All frequency standards offer multiple buffered outputs (5x or 10x outputs of 10 MHz sine). Choose from the low-cost 6688 based on a very-high-stability oven-controlled SC-cut crystal oscillator or the 6689 with a built-in Rubidium atomic clock. These standards are suited for use in automatic test systems, for example in the production department of telecommunications companies, especially when multiple instruments/testers need to be supplied with a stable frequency reference.

The very short warm-up time of only 10 minutes makes these units suitable also for field use.
  • Stand-alone frequency reference standard
  • Rubidium (6689) or high stability ovenized crystal oscillator (6688)
  • Distribution amplifiers for 5x10 MHz and 1x5 MHz outputs as standard
  • Optional 10x10 MHz outputs
  • 0.001 ppm aging in 10 years (Rubidium)