PicoScope 5000 Series

Flexible resolution oscilloscopes

PicoScope 5000 Series - Elektra Awards Winner 2013

High speed and high resolution. Breakthrough ADC technology switches from 8 to 16 bits in the same oscilloscope.

From just £739.00

More

Experiment to view T1 clock recovery

 

Educational data logger

This experiment demonstrates how a T1 data communications code can be viewed by the ADC-200/20 oscilloscope and how a simple circuit can alter the code to recover the embedded clock signal. The figure below illustrates various baseband data codes and their respective frequency spectra. The T1 signal is the Bipolar AMI RZ.

image showing the waveforms for communication data

This experiment demonstrates:

  • What a very popular serial data communications signal looks like.
  • What the frequency spectrum of that signal looks like.
  • A simple circuit to extract the embedded clock signal in the data for signal regeneration purposes.

This experiment is suitable for: 

  • College or University Data Communications Course.
  • Data Communications Professionals Carrier/ISP.

Equipment required

  • ADC-200/20 oscilloscope running PicoScope oscilloscope software.
  • T1 Test Generator. Wandel & Goltermann DSA15.
  • Coaxial cable with BNC T Connector terminated in 100 ohms.
  • 2 x alligator clips
  • Diode bridge (4 diodes soldered in bridge configuration 1N914)

Safety

Always keep in mind that the ground of the ADC-200/20 is common to the ground of the PC and thus common to AC ground.

Experiment setup

The setup is shown in the sketch and picture below:

connection of the ADC-200 to the test set up

Figure 1: experiment set up

Experiment procedure

1. T1 test set direct to ADC-200/20

Using the correct bantam test cord, connect the T1 test set output directly to the Ch1 input on the ADC-200/20. A coaxial cable with alligator clips can be used to connect to the tip and ring on the balanced bantam cable. Ensure that the Ch1 input is terminated in the correct T1 impedance of 100 ohms.

Set the T1 test set for the standard Bell QRSS test waveform. This generates a predetermined stream of random bits. This waveform can be easily captured by the ADC-200/20 in single shot mode. The capture is shown below:

random data captured by PicoScope from the ADC-200

The spectrum of the QRSS signal is shown in the first figure. It is a smooth hump with very little energy at DC, peak at 772 kHz, and null at the bit rate of 1.544 MHz. The spectral capture on the ADC-200/20 is shown below.

captured frequency spectrum using PicoScope

2. T1 clock recovery

In order for a digital signal to be useful, it must be periodically regenerated to remove unwanted noise. To do this, a clock signal must be present at the data rate for sampling purposes. In order to do this, the T1 signal can simply be put into a full wave diode bridge. 4 ordinary diodes like 1N914 diodes can be used for this purpose as shown below.

full wave rectifier

Connect the T1 test set with alligator clips so that the signal is at the AC points of the bridge. The ADC-200/20 tip will connect to the positive of the bridge and the ring to the negative.

The T1 signal is now rectified and the capture is shown below.

captured screenshot of rectfied signal using PicoScope

The spectrum of the rectified T1 signal now shows a strong recovered clock at the bit rate of 1.544 MHz!

spectrum of rectified signal using PicoScope

Credits, comments and further info

This experiment was written by Jeremy Clark and Kyle James Mcneil at Seneca College, Canada.

Testimonials

  • I have been using my 4224 PicoScope for years. I travel abroad so this has been ideal due to its physical size. Storage of waveforms on my Laptop is very easy allowing me to quickly email waveforms to my Colleagues.

    Andrew
  • Not many USB scopes works on Win & Mac & Linux too, so that proves me that guys from Pico really cares about us, customers. This made my decision much easier when I was looking to buy an USB scope.

    Raul Trifan
  • We have been using Picoscope 6404D for quite some time, and are amazed by its accuracy and powerful emulations while working with numerous signal evaluations.

    J Mohanty
  • PicoLog TC-08: This is a very nice unit that works consistently and reliably.

    Jeff Hulett
  • It is a great scope. I had a weird problem - it did not work on one of my PC’s. Customer service gave me first class service. If I could give 6 stars for customer service - I would do so.

    Niels Larsen
  • Perfect Partner for Development of Encoder controlled Stepper Motor Actuators. Since the included software is really stable, this type of device is a great tool for great tasks!

    Helmut Schoettner
  • A superb piece of equipment worth its weight in gold

    Nigel Clinch
  • So simple to use & beats any other I have ever used hands down.

    John D Samsing
  • Great functionality in a compact size. I really like moving the mouse pointer to a position and having the Time and Voltage display the values at that point. Calibration equipment is a breeze with that feature.

    Don Horein

PC oscilloscope and data logger products

Tel: +1 800 591 2796 (Toll Free)