September 21, 2015 Phoenix, AZ: Picotest.com, a leader in high resolution test and measurement equipment, has released a new test signal generator for EMI testing applications. The USB Harmonic Comb Injector, the latest edition to Picotest’s popular line of Signal Injectors, is a fast, easy-to-use, ultra-portable harmonic comb signal generator for interrogating your Power Distribution Networks (‘PDN’) to identify noise sensitivities. A comb signal generator is simply a device that produces a set of harmonically related CW signals whose spacing is based on a fundamental oscillator frequency. Other applications include a general purpose source for characterizing semi-anechoic chambers (for measurement consistency day-to-day, and comparing one chamber to another) and as a source for measuring cable, or other metallic structure, resonances especially for those who do not have access to a tracking generator on their spectrum analyzers, or those who do not have a network analyzer.

The comb injector includes impulse & square wave outputs and has multiple modes of operation including time and frequency jitter. It is designed for power supply and clock EMI spectrum testing and has a usable frequency range of 1kHz to 1.5GHz with edges as fast as 300ps. The comb injector is USB powered with a single SMA output connector. No external power supply is necessary.

There are 5 modes of operation available including 1kHz impulse, 100kHz impulse, and 8MHz impulse output, each with frequency and pulse width dithering, a stepped mode that continuously steps between the three impulse modes and a 1kHz square wave output mode that is convenient for step load testing. Modes are changed via a convenient pushbutton on the injector key with a color LED indication of the active mode.

“The Picotest Harmonic Comb Injector is different from standard signal generators”, explains Kenneth Wyatt, EMI test expert (The EMC Blog (http://www.edn.com/electronics-blogs/4376432/The-EMC-Blog), and here (http://design-4-emc.com/)). The ability to adjust the comb frequency from kHz to MHz is especially useful, eliminating the need to purchase multiple fixed frequency comb generators. “For example, I would use the lower frequency combs to determine structure or cable resonance in order to achieve the best resolution, but the 8 MHz combs for test chamber validation where such fine detail is not as important. Combined with a small monopole antenna and USB battery-powered voltage source, this is one tool that every EMC test lab should own to help validate their chamber measurements.”

“The portability of this EMI injector is an advantage over current competitive solutions. The variable frequency comb is tremendously useful accessory to the Keysight E5052B and N9020A, Tektronix RSA5106A and RSA306, R&S FSW, FSMR and FSUP and virtually all oscilloscopes” says Steve Sandler, CEO of Picotest. “With it I can conveniently test Power Integrity and various EMI performance characteristics without having to carry around an AWG.”

The price of the Comb Injector is $895 in single quantities and is available now from www.Picotest.com. The Injector is compatible with all 50 ohm instruments.

Selected Specifications:

  • -13dBm typical 1kHz and 100kHz
  • -17dBm typical 8MHz
  • 10kHz square wave 13dBm, typical Duty cycle 50% typical
  • DC coupled 0 to +2.5V pulse into 50Ohms
  • Typical rise/fall time 470ps/270ps

A Picotest Harmonic Comb Injector output pulse.

About Picotest

Picotest, founded in 2010, is a company dedicated to providing instruments, accessories and training to support electronic test and measurements, with an emphasis on Power Integrity solutions. Picotest is headquartered in Phoenix, AZ. For more information on Picotest, please contact the company at 1-877-914-PICO.

All logos and trademarks in this release are the property of their respective owners.

The Picotest Harmonic Comb Injector. 

The spectrum of 125MHz clock jitter with the Picotest Harmonic Comb Injector connected to the clock power rail. Measurment is shown on the Rhode & Schwarz spectrum analyzer. Note the 7MHz resonance identified by the Harmonic Comb Generator.

The spectrum of 125MHz clock jitter with the Picotest Harmonic Comb Injector connected to the clock power rail. Measurment is shown on the Keysight N9020A spectrum analyzer. Note the 7MHz resonance identified by the Harmonic Comb Generator.