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Multi-Tone System FAQ

Multi-Tone System FAQ

  • What is a Multi Tone test system? How does it work?
  • The concept of Multi-tone testing is simple. Rather than testing a single frequency during every dwell period, multiple frequencies are tested at the same time.

    While simple in concept, the actual hardware implementation has always been a hurdle. Simultaneously controlling multiple signal sources and properly combining their output signals in a repeatable fashion has been beyond the scope of traditional, analog test instrumentation.

    The solution is the combined use of two devices: a Vector Signal Generator (VSG), which can digitally produce multiple tones and complex modulations, and a frequency selective power measurement device, such as a Vector Signal Analyzer (VSA). Using this digital instrumentation under software control, the multiple tones necessary can be generated, measured, and controlled.
  • Will the IEC 61000-4-3 standard allow multi tone testing?
  • Allowances for multi tone testing have been added to the IEC 61000-4-3 and accepted by the WG10 (working group supporting the IEC 61000-4-3) along with an informative Annex describing the effects of intermodulation. However, multi-tone testing can be performed today. In the event of a failure revert to single tone testing.
  • How does the Multi Tone system save time?
  • Multi-Tone Time Savings ChartMulti tone system saves time by utilizing the dwell time. Since the dwell time is fixed per the standards- and most of the test time is spent during the dwell, if you generate multiple tones during each dwell time this will significantly reduce test time. For example; by generating 6 tones during the dwell there is a test time savings of 82% for a typical IEC 61000-4-3 radiated immunity test to 6 GHz.
  • Why would one purchase the Multi Tone system?
  • The main reason to purchase a multi tone system is to save test time and associated cost. That equates to savings in man-hours as well as more cost-effective use of your equipment and increased throughput and efficiency of your testing facility.
  • Is the multi tone method over testing the EUT?
  • The short answer is yes; however, you have the option to reduce to a single tone if the EUT fails. Remember that the unit is being exposed to multiple tones and each tone has a field strength equal to the required test level. Each of these tones will have slightly different phases, so there will be additive and subtractive components to the total energy presented at the EUT. The peak of this total power is only reached when all the signals are in phase for a relatively short occurrence.
  • How much amplifier power is required?
  • That depends on the number of tones being generated at a time. For each tone the average power is approximately additive, whereas the instantaneous power may be as high as the square of the number of tones generated. The average power is used to calculate the required amplifier power.
  • Can the Multi Tone system be used for IEC 61000-4-3, 16-point Calibration?
  • No, this test standard very clearly explains the calibration and testing procedure which must be followed to demonstrate compliance. The lengthy 16-point calibration process uses isotropic field probes which are not frequency selective and cannot parse out and measure multiple tones. Therefore, the calibration time cannot be improved using a multi-tone process. However, the Multi Tone system can still be used in a single tone mode to perform the calibration.
  • What are the limitations of the Multi Tone system?
  • The most significant limitations of the multi tone system are the amplifier power, the bandwidth of the VSG and the field probe limitations.
  • What equipment is included with the Multi Tone system?
  • The multi tone system consist of a field probe with a field monitor and fiber optic cable. A system controller that switches up to 4 amplifiers and 4 antennas for automated testing. A vector signal generator (VSG) to generate multiple tones and a vector signal analyzer (VSA) to measure the tones.
  • Do I need to purchase a special software to run Multi Tone system?
  • No, the Multi Tone system uses the in-built Multi Star software to perform testing.
  • Will users need to purchase power amplifiers with a lot more power to drive multiple signals not to mention the multipath issues that will show up from time to time?
  • Yes, with multiple signals require a larger amplifier to generate the proper field strength.

    Note: The chamber multipath issue will occur with a single signal.
  • Can user able to save test profile once created?
  • Yes, once you create a test set-up you can save the file with all of the test settings for future use, saving valuable time. Additionally, calibration information for all equipment as saved, including appropriate correction factors.

To learn more about AR's Multi-Tone Test Systems contact your local AR sales representative, or email us at