5125A Test Set

5125A Test Set

High-Performance, Extended-Range Phase Noise and Allan Deviation Test Set

The 5125A makes accurate phase-noise measurements on signals from 1 MHz to 400 MHz, covering the full range of the most commonly used frequency references. The 5125A, which requires absolutely no configuration, displays measurement results seconds after the Start button is pressed.


Over 25 years of research at the National Institute of Standards and Technology (NIST) and in private industry have come to fruition in Symmetricom's phase noise test sets, which employ both direct sampling of the RF waveforms as well as cross correlation, making it possible to easily characterize the highest performance time and frequency references. The third generation, all-digital 5125A has been designed to meet the most demanding requirements. The 5125A can measure phase noise down to -145 dBc/Hz at 1 Hz offset from a 10 MHz carrier and -130 dBc/Hz at 1 Hz offset from a 100 MHz carrier, making it the perfect solution to characterize the very low noise frequency references, such as those used in RADAR and satellite communications.


The all-digital architecture employed in the 5125A uses advanced, high-speed, low-noise analog-to-digital converters in a patented architecture that does not require a phase-lock loop to make measurements. This provides multiple benefits for 5125A users:

  • Measurements are extremely easy to make, with no pre-calibration or configuration required.
  • Accurate results are presented within seconds of a measurement having been started.
  • Input carrier signals can be characterized much more accurately than before, to within 0.1 mHz of the carrier.
  • The stability or Allan deviation is measured in parallel with phase noise. The 5125A also includes a frequency counter with 13 digits of precision

Key Features

  • Simultaneous Phase-Noise and Allan-Deviation Measurements
  • 1 - 400 MHz Input Frequency Range
  • Measurement Results Displayed within Seconds
  • No External Data Processing Required
  • Industry Leading Accuracy
  • Makes Measurements with Input and Reference at Different Frequencies
  • Allan-Deviation Measurements to over 300 Days
  • Phase-Noise Measurements as Close as 0.1 mHz from the Carrier
  • No Measurement Calibration Required: saves time
  • Displays Internal Noise Estimate
  • Easy to Use Graphical User Interface
  • Excellent Phase-Noise Measurements Down to -170 dBc/Hz (typical) 10 kHz from the carrier (10 MHz input)


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Amtest-TM Kft. (HU) - Tibor Csombordi Amtest PL (PL) - Dariusz Koziello Amtest-TM ELTH srl (RO) - Bogdan Valcea ADELANTEST Ltd (RUS) - Igor Kozlov GIGA ELECTRONICS EOOD - Danail Georgiev OÜ Est-Doma (EST) Promix Ltd. (UA) - Oleksandr Labuzov Vildoma (LT, LV)

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