Multi-Tone System FAQ
- What is multiple signal testing? How does it work?
Rather than testing a single frequency during every dwell period, multiple signals, also referred to as multi-tones, are generated to simultaneously test multiple frequencies.
While simple in concept, the actual software and 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.
One possible solution includes the use of a Vector Signal Transceiver (VST), which incorporates the functionality of both a Vector Signal Generator (VSG) and Vector Signal Analyzer (VSA). Using this digital instrumentation under the proper software control allows multiple tones to be generated, measured, and controlled.
- Will the IEC 61000-4-3 standard allow multiple signal testing?
- Allowances for multiple signal testing were added to the 4th edition of IEC 61000-4-3. Annex I of this standard contains useful information regarding multiple signal testing, also known as multi-tone testing, such as: concerns relating to intermodulation, power requirements, level setting requirements, linearity and harmonics check, and EUT performance criteria with multiple signals. For those sectors still in the adoption phase of this test approach, multiple signal testing is still acceptable. In the event of a failure you will need to revert to the traditional single tone testing.
- Is the multiple signal method over-testing the EUT?
- The short answer is yes; however, you have the option to reduce to a single signal, or 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.
- What is the benefit of purchasing the AR Multi-Tone System?
- The main reason to purchase AR's MT06002 System is to save test time and associated cost. That equates to savings in man-hours as well as a more cost-effective use of your equipment resulting in increased throughput and efficiency of your testing facility.
- How does the Multi-Tone System save time?
- The Multi-Tone System saves time by producing multiple signals during a dwell time. Since the minimum dwell time is defined by the harmonized standards and the cycle time of the EUT, and a large part of the total test time is spent during the dwell, multiple tones executed during each dwell 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 when compared to testing a single tone.
- Can the Multi-Tone System be used for IEC 61000-4-3, 16-point Calibration?
- Yes, AR's Multi-Tone System can be used for IEC 61000-4-3, 16-point calibration using a single tone. The use of a Vector Signal Transceiver (VST) improves the data throughput through its ability to more efficiently generate, receive and process information, as compared to traditional computer-controlled systems. It should be noted that when performing the 16-point uniform field area (UFA) calibration, using simultaneously generated multiple signals is not an acceptable or approved method due to the inability of field probes to distinguish or produce measured RF field strengths of simultaneously generator RF fields. If you choose to perform the 16-point field calibration, the MT06002 has this capability.
- What are the limitations of the Multi-Tone System?
- The most significant limitations of a multiple signal test system is the amplifier power, the MT06002 bandwidth (up to 1 GHz), and field probe bandwidth limitations.
- How much amplifier power is required?
- That depends on the number of signals, or 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.
- Will users need to purchase power amplifiers with a lot more power to drive multiple signals?
- The MT06002 will use your current amplifiers more efficiently, so it is possible to use existing amplifiers and still benefit from multiple signal testing. For instance, when performing an IEC 61000-4-3 test within the frequency range of 80 – 1000 MHz, more power is required from 80 – 200 MHz than from 200 – 1000 MHz due to antenna efficiencies. In the case of an AR W-series amplifier, which operates from 80 – 1000 MHz, the amplifier will need to be sized for the 80 – 200 MHz range. The MT06002 will analyze the amplifier's available power and signal compression to determine the frequency ranges where multiple tones can be applied, as well as the number of tones that can be generated. Therefore, in the 200 – 1000 MHz range, more amplifier power will be available and the MT06002 can thus create more tones.
- What equipment is included with the Multi-Tone System?
The AR MT06002 Multi-Tone system consists of the following:
- 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 transceiver (VST) to generate multiple signals or tones, and to simultaneously measure the tones.
- Up to 1 GHz instantaneous bandwidth
- Do I need to purchase a special software to run Multi-Tone System?
- No, the AR Multi-Tone system uses the built-in MultiStar software to perform testing. This software is developed by AR software and EMC Engineers.
- Is the user able to save a test profile once created?
- Yes, once you create a test set-up you can save the file with all the test settings for future use, saving valuable time. Additionally, calibration information for all equipment is 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 email@example.com.