Related Manuals for Picotest J2150A
Summary of Contents for Picotest J2150A
- Page 1 USB Harmonic Comb Injector Documentation Version 1.2, February 2020 Copyright © 2016 Picotest All Rights Reserved...
- Page 2 Trademarks The Picotest logo and “Picotest Harmonic Comb Injector” are trademarks of Picotest Corp. All other brand and product names mentioned herein are used for identification purposes only and are registered trademarks, trademarks, or service marks of their respective holders.
-
Page 3: Table Of Contents
Table of Contents Chapter 1 - Overview ...................... 4 Welcome ............................4 What’s Included ..........................5 Documentation and Support ......................5 Warranty ............................5 Calibration ............................5 Chapter 2 – Introduction to the Harmonic Comb ............6 Introduction and Usage ........................6 Connecting the Comb ........................ -
Page 4: Chapter 1 - Overview
Chapter 1 - Overview Welcome Thank you for purchasing Picotest’s J2150A USB Harmonic Comb Injector. The Harmonic Comb Injector is an ultra-portable multifunction signal generator. 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. -
Page 5: What's Included
Picotest Harmonic Comb. Warranty Every Picotest product you buy from Picotest.com is backed by a 1-year manufacturer’s warranty. For warranty service or repair this product must be returned to a service facility designated by PICOTEST. Please contact your local service representative for further assistance. -
Page 6: Chapter 2 - Introduction To The Harmonic Comb
Harmonic Comb Chapter 2 – Introduction to the Harmonic Comb Introduction and Usage The Harmonic Comb Injector is a simple to use signal generator designed to support Power Integrity and EMC/EMI testing applications. You can use the Comb to reveal resonances in power supply and voltage bus designs, as well as to support EMC/EMI measurement and troubleshooting. -
Page 7: Connecting The Comb
Harmonic Comb Mode 1 is the default mode at power-up, and steps through modes 2 through 4 in order to excite all harmonic frequencies - thus quickly revealing problem resonances. Modes 1 through 4 include pulse width dithering to help fill in gaps between combs. Once resonant frequencies are identified in Mode 1, Modes 2 through 4, with frequencies of 1 kHz, 100 kHz, and 10 MHz, respectively, may be used to zero in on specific resonances. - Page 8 • the SMA output connector. The output is DC-coupled, so the signal may be used to modulate other Picotest voltage and current injectors. The output voltage is 5V into a high impedance termination, 2.5V into 50 ohms. In order to AC-couple the output, a Picotest P2130A DC Blocker (shown below) may be used.
-
Page 9: Changing The Comb Mode
Harmonic Comb Changing the Comb Mode To change the Harmonic Comb mode: • Press the large ‘Mode’ button on the top of the Comb for at least 1 second. • The current mode is indicated by three LEDs as shown in the table below. Mode Description Yellow... - Page 10 Harmonic Comb Figure 1: Pulses from the Comb are shaped and run into a driver circuit that creates a 470 ps rise and 270 ps fall time (typical). Figures 2: The spectrum when using Mode 2 (1 kHz dithered fundamental).
- Page 11 Harmonic Comb Figures 3: The spectrum when using Mode 3 (100 kHz dithered fundamental). Figure 4: This figure shows a typical harmonic output up to 1 GHz when using Mode 4 (10 MHz dithered fundamental). This mode would be useful for verification of EMI test chambers.
- Page 12 Harmonic Comb Figure 5: Mode 1 (default sweep mode) includes stepped impulse responses with frequency and width dithering. Figure 6: 10kHz square wave (~50% duty). Mode 5 produces a 10kHz pulse with a duty cycle of approximately 50% as noted by the low level of even harmonics. This pulse can be used to modulate a current injector or as a calibration edge.
-
Page 13: Sample Harmonic Comb Applications
EMI due to ringing on switched waveforms. Picotest has one- and two-port probes that may be used, along with the Harmonic Comb Injector, to hunt for problem resonances within your power bus circuitry. Shown below are several such examples. - Page 14 Harmonic Comb Figure 8: The LDO and Clock circuitry.
- Page 15 Harmonic Comb Figure 9: Test setup for measuring resonances within the power bus structure. With the spectrum analyzer centered on 125 MHz, you can readily observe a 7 MHz resonance as sidebands of the clock.
- Page 16 Harmonic Comb Figure 10: Power bus resonances at 7 MHz are shown as sidebands to the 125 MHz clock. Figure 11: By adding an additional 15 uF capacitor to the 3.3V bus, the resonance is eliminated.
-
Page 17: Chapter 3 - Specification
Specifications that are not defined to be guaranteed are typical and are published as general information to the user. The instrument should have warmed-up for at least 20 minutes and the environmental conditions do not exceed the Comb's specified limits. Harmonic Comb Specifications J2150A Characteristic Rating Output... -
Page 18: Handling Information
Harmonic Comb Use only grounded instruments. Do not connect the Comb ground (USB connector) to a potential other than ground or earth ground or to any power source that isn’t grounded. Always make sure the Comb and the measurement instrument/power source are grounded properly. Observe Comb ratings.
Need help?
Do you have a question about the J2150A and is the answer not in the manual?
Questions and answers