Test and Measurement News

September 2008

New Persistence Display Modes for PicoScope

The latest release of the PicoScope software, version 6.1.0, has two new display modes to help you find glitches and measure noise and jitter. Unlike the standard display mode, which erases each old waveform before drawing a new one, the new persistence modes keep old waveforms in the background and draw new waveforms over the top of them.

In digital colour mode, frequently repeating waveforms are drawn in a “hot” colour (red), while intermittent waveforms appear in “cooler” colours (yellow and blue). In analog intensity mode, new waveforms are drawn with maximum contrast while older waveforms fade to paler colours. You can also change the default colours from theTools | Preferences menu.

To start persistence mode, just click the new Persistence Mode button on the toolbar. Click the other new button on the toolbar, Persistence Options, to customise the display. Here’s how this new feature can help you:

  • Find glitches. Trigger on a repetitive waveform that you suspect might have an intermittent glitch, and then select digital colour mode. Once you have found the glitch, switch to standard scope mode where you can set up an advanced trigger, capture the glitch at full resolution and add automatic measurements.
  • Estimate noise. Persistence mode displays a spread of data values at each sampling point, with the hotter colours showing the mean value of the signal and the colder colours showing the noise. You can estimate the peak-to-peak noise by measuring the height of the cold-coloured region.
  • Estimate jitter. PicoScope shows the mean location of an edge in the hottest colours. Edges that deviate from the mean location, because of intermittent timing errors or random jitter, appear in colder colours. As with noise, you can estimate the peak-to-peak jitter by measuring the width of the cold-coloured region.
  • Display eye patterns. If you are troubleshooting a serial data stream or high-frequency data line, you can use persistence mode to display an eye pattern. Trigger on a stable clock source from the device under test, and set the PicoScope timebase to show about two bit periods across the screen with one bit period in the centre of the display. Persistence mode will then show you a colour-coded eye pattern. You can use PicoScope’s measurement rulers to estimate parameters such as jitter, noise margins, overshoot and eye opening.
  • View analog video and modulated waveforms. These waveforms are best viewed in analog intensity mode. The densest parts of the waveform appear in the strongest colour, giving an intensity-graded waveform that resembles an analog CRT oscilloscope display.

Read more about the new persistence modes
Download the latest version of PicoScope 6

If you don’t yet own a PicoScope oscilloscope, you can still run PicoScope 6 in demonstration mode and try out all of its features.

PicoScope 6 Tech Tip: Waveform File Sizes

Have you ever saved a*.psdwaveform file using PicoScope 6 and then wondered why the file was too small? This happens because PicoScope 6 compresses waveforms when it saves them on your hard drive. It uses “lossless compression”, which means that when you load the waveform back into PicoScope you get exactly the same data that you started with, with no distortion. Compressed waveforms take up less space on your hard drive than raw waveforms, typically only a quarter as much, although the exact compression ratio depends on the content of the waveform. As the buffer sizes of our oscilloscopes get larger (our biggest to date is the PicoScope 5204, with up to 128 megasamples per waveform), this compression feature is likely to become even more valuable.

Find out more about PicoScope 6 oscilloscope software

Independent Review of the PicoScope 9201

EN-Genius Network has published an independent review of the PicoScope 9201 PC Sampling Oscilloscope. The review explains how the PicoScope 9201 differs from real-time oscilloscopes, and predicts that it “will give major oscilloscope vendors a run for their money”.

The two-channel 12 GHz PicoScope 9201 sampling oscilloscope costs under £6,000 (about $12,000 or €8,000), less than half the price of comparable sampling oscilloscopes. Unlike sampling scopes from other manufacturers, the PicoScope 9201 includes all hardware and software functions as standard, with software updates provided free of charge. It is the perfect instrument for signal analysis, timing analysis, testing and design of high-speed digital communication systems, network analysis, semiconductor testing, and research and development.

Read full details of the PicoScope 9201 and request an information pack

New Heavy-duty Thermocouple Loggers

We are developing two new thermocouple data loggers in die-cast metal enclosures: the TC-08R with 8 channels and the TC-32R with 32. Electrical specifications are the same as those of the standard USB TC-08. Here are the main points:

  • Measures from -270 to +1820 °C
  • Compatible with all common thermocouple types: B, E, J, K, N, R, S, T
  • Automatic cold junction compensation
  • High resolution and accuracy
  • Fast sampling rate
  • Multiple units can be run on a single PC
  • USB interface

New Pressure Sensor

Recently we announced the new WPS500X Diagnostic Pressure Transducer for automotive use, but we think it will also be of interest to non-automotive customers. This ultra-high-resolution sensor can measure a wide range of pressures, making it a cost-effective alternative to more specialist types. Here are just a few of the applications:

  • Hydraulics
  • Jet washers
  • Water heating systems
  • Gas pipelines
  • Pneumatic systems

The transducer features three pressure ranges: 0 to 500 psi, 0 to 50 psi and ±5 psi, pressure relief valve and a rechargeable Li-Po battery all enclosed in a durable housing. It has an extremely fast 100 µs response rate from 0% to 90% of full scale and sensitivity down to about 5 millibar (about 0.07 psi). This provides accurate representation of rapidly changing signals across a wide pressure range. Also included is a unique zoom function that allows users to ‘zoom in’ on small signals.

The sensor is priced at $765 (about º383 or €566), which could save you hundreds of pounds compared to a set of application-specific transducers with the same capabilities.

Questions and Answers

Here is a selection of the questions that have cropped up recently on our support forum.

Q. I am getting strange readings from my K-type thermocouples. When I touch the thermocouple, the temperature drops and does not change until I let go. I then noticed that when I touch and hold a different one of my 6 thermocouples, all of the readings change. I am planning on testing a DC generator’s heat output. Would the field or current that the generator produces affect the readings as well?

A. This effect sounds like a common-mode voltage problem. If, by touching the uninsulated end of one of the thermocouples, you cause it to be pulled out of the common-mode voltage range of the TC-08 (±5 V), then all channels will be affected. This voltage is either caused by conduction to earth through your body where the mains earth is at a different voltage to local earth or direct pickup of radiated interference. Just ensure that in normal use the uninsulated end of the thermocouple is not electrically connected to the metal structure of the generator being tested. (Good thermal contact is necessary, though.) Sometimes screening of the thermocouple leads is also necessary in high-noise areas.

Q. I am using an ADC-11/10 with PicoLog, and I wish to start recording on channel 2 when a trigger signal occurs on channel 1. How do I make PicoLog start recording?

A. Here are some points to check when using the trigger function with PicoLog:

  • Make sure you have specified a data file with the File -> New Data command
  • Set the Recording Mode to Fast Block
  • Deselect the Auto trigger option in the ADC11/22 dialog
  • Click the Start Recording button in the Recorder to arm the trigger

Events

Please visit Pico Exhibitions for the latest list of exhibitions and trade shows that Pico and its representatives will be attending.

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Thanks to our continuing success and growth Pico are always seeking talented people to join our company.

Please visit https://jobs.picotech.com/ to see our current vacancies. We look forward to hearing from you!

Software releases

Our latest software releases are available as free downloads. To check which release you are using, start the software and select Help > About.

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Contact details

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