PicoScope software dedicates almost all of the display area to the waveform. This ensures that the maximum amount of data is seen at once. The viewing area is much bigger and of a higher resolution than with a traditional benchtop scope. With a large display area available, you can also create a customizable split-screen display, and view multiple channels or different views of the same signal at the same time. As the example opposite shows, the software can even show both oscilloscope and spectrum analyzer traces at once. Additionally, each waveform shown works with individual zoom, pan, and filter settings for ultimate flexibility.
The PicoScope software can be controlled by mouse, touchscreen or keyboard shortcuts.
Alarms are actions that PicoScope can be programmed to execute when certain events occur. The events that can trigger an alarm are:
The actions that PicoScope can execute are:
Alarms, coupled with mask limit testing, help to quickly validate signal quality in electronic system designs. Testing can be done over extended periods of time and while parameters such as supply voltage or temperature are changed to validate that the design operates reliably over the full range of specified operating conditions.
Also called DC offset, this is a valuable feature available on many PicoScope oscilloscopes. When used correctly, it can give you back the vertical resolution that would otherwise be lost when measuring small signals.
Analog offset adds a DC voltage to the input signal. If the signal is out of range of the scope’s analog-to-digital converter (ADC), the offset can be used to bring the signal back in range allowing a more sensitive range to be used.
An arbitrary waveform generator (AWG) is used to generate electrical waveforms. The waveforms can be either repetitive or single-shot. An AWG can generate any arbitrarily defined waveshape as its output. The waveforms can be injected into a device under test and analyzed by the PicoScope as they progress through it, confirming proper operation of the device or pinpointing a fault in it.
ARINC 429, also known as the Mark 33 DITS specification, was developed to provide interchangeability and interoperability of line replaceable units (LRUs) in commercial aircraft. ARINC 429 defines the physical and electrical interfaces of a two-wire data bus and the data protocol to support an aircraft's avionics local area network.
The physical connection wires are twisted pairs carrying balanced differential signaling. Data words are 32 bits in length and most messages consist of a single data word. Messages are transmitted at either 12.5 or 100 kbit/s. The transmitter constantly transmits either 32-bit data words or the NULL state. Most ARINC messages contain only one data word consisting of either binary (BNR), binary coded decimal (BCD), or alphanumeric data encoded using ISO Alphabet No. 5. File data transfers that send more than one word are also allowed.
ARINC 429 employs several techniques to minimize electromagnetic interference (EMI) with on-board radios and other equipment.
In addition to twisted-pair cabling, ARINC signaling defines a 10 V peak differential signal, with acceptable voltage rise and fall times for the Data A and Data B levels, and complementary differential bipolar return-to-zero (BPRZ) data encoding to minimize EMI emissions from the cable itself.
If you have lots of input channels, reference channels and math channels enabled, it can take time to move them around and scale them so that they are all clearly visible. By right-clicking on a view and selecting Auto-Arrange Axes, all the traces are automatically shifted and scaled so that none of them overlap.
Oscilloscope bandwidth is defined as the frequency at which a sine wave input signal is attenuated to 70.7% of the signal’s true amplitude, known as the –3 dB point, a term based on a logarithmic scale.
Bandwidth determines an oscilloscope’s fundamental ability to measure a signal. As signal frequency increases, the capability of the oscilloscope to accurately display the signal decreases.
Without adequate bandwidth, high-frequency signals will be displayed with lower amplitude than the true signal. Rise and fall times will appear slower than the true signal. A common rule of thumb, to achieve better than 3% measurement accuracy, is to use an oscilloscope with five times more bandwidth than the fastest signal component you need to measure.
This is the default mode used by PicoScope software. The scope stores data in internal buffer memory, then processes it and transfers it to the PC before starting the next block.
In the illustration shown, the buffer memory is shared between the two channels on the oscilloscope, allowing two waveforms to be captured in a single run.
Block capture mode gives access to the scope’s fastest real-time sampling rates.
The internal buffer memory can be segmented to allow many waveforms to be collected. Acquisitions continue on a first-in-first-out basis until stopped by the user, or unless the scope is set to "Single" trigger.
PicoScope buffer sizes are specified in kS (kilosamples), MS (megasamples) or GS (gigasamples). The makers of the memory chips that we use in PicoScope oscilloscopes usually state memory sizes as powers of 2, and we follow this convention in our specifications. Here is what we actually mean by kS, MS and GS:
|Unit||Power of 2||Decimal equivalent|
|kS||210||1 024 samples|
|MS||220||1 048 576 samples|
|GS||230||1 073 741 824 samples|
As you can see, these numbers are close but not equal to one thousand, one million and one billion. So, if you buy an oscilloscope with a 1 MS buffer size, don't be surprised if you see a sample count slightly higher than 1 million in the PicoScope Properties panel.
There are also many cases when the PicoScope 6 software gives you a sample count that is lower than the buffer size of your oscilloscope. This happens when PicoScope is in a repeat triggering mode and needs to use part of the memory for storing the next capture. It also happens when you have divided the memory into segments, and the number of segments that you have requested does not fit exactly into the available memory. To ensure that PicoScope 6 captures the greatest possible number of samples, set the Trigger control to Single and the Number of Samples control to a number greater than the buffer size of the oscilloscope.
All PicoScopes are tested to ensure they meet their specifications. This means that you can be confident that all measurements you make with your Pico product will be within the accuracy that we specify.
If you plan to use your product in an industrial or scientific environment where it is necessary to have documented traceability, or you just want your Pico product to be ‘fine-tuned’ to give the best possible performance, then for most of our products we can provide you with a calibration service referenced to National Standards. This means that you will be given documented proof of the accuracy of your Pico product at the time it is despatched to you. This documented proof is in the form of a calibration certificate that has the errors recorded. For example, the product may have a published accuracy of ±3%, and after calibration the error might be recorded as –1%. You can then allow for this –1% error when taking measurements.
For best accuracy, we suggest that a calibrated product is recalibrated yearly.
CAN bus (Controller Area Network) is a one or two wire system originally designed for automotive applications, but is now also deployed in applications such as aerospace and process automation.
The protocol was officially released in 1986 at the Society of Automotive Engineers (SAE) congress. The CAN protocol defines two standards:
The International Organization for Standardization released the CAN standard ISO11898 which covers high and low speed definitions
The CAN bus defines how devices called nodes communicate on a single or dual-wired network. The dual-wired network is a differential system and therefore has improved noise and interference rejection over the single wired system.
CAN waveforms can be decoded with PicoScope: From the Tools menu select Serial Decoding then Create and select CAN from the list of available protocols.
The custom probes feature allows you to correct for gain, attenuation, offsets and nonlinearities in probes, sensors or transducers that you connect to the oscilloscope. A simple use would be to linearly scale the output of a current probe so that it correctly displays amperes. A more advanced use would be to scale the output of a nonlinear temperature sensor using the table lookup function.
Definitions for standard Pico-supplied oscilloscope probes and current clamps are included. User-created probes may be saved for later use.
PicoScope deep-memory oscilloscopes have waveform buffer sizes up to 2 gigasamples – many times larger than competing scopes of either PC-based or traditional benchtop design. Most other scopes with large buffers slow down when trying to use a lot of memory, so you have to manually adjust the buffer size to suit each application. You don’t have to worry about this with PicoScope deep-memory scopes as hardware acceleration ensures you can always use deep memory while displaying at full speed.
Deep memory produces several benefits: fast sampling at long timebases, timebase zoom, and memory segmentation to let you capture a sequence of events.
The majority of digital oscilloscopes still use an analog trigger architecture based on comparators. This causes time and amplitude errors that cannot always be calibrated out and often limits the trigger sensitivity at high bandwidths.
In 1991 Pico pioneered the use of fully digital triggering using the actual digitized data. This technique reduces trigger errors and allows our oscilloscopes to trigger on the smallest signals, even at the full bandwidth. Trigger levels and hysteresis can be set with high precision and resolution.
The reduced rearm delay provided by digital triggering, together with segmented memory, allows the capture of events that happen in rapid sequence. On many of our products, rapid triggering can capture a new waveform every microsecond until the buffer is full.
Equivalent time sampling (ETS) is method of increasing the effective sampling rate of the scope.
Equivalent-time sampling builds a picture of a repetitive signal by capturing small parts of the waveform from successive triggered acquisitions. This allows PicoScope to accurately capture signals whose frequency components are much higher than the maximum sample rate.
For accurate results, the signal must be perfectly repetitive and the trigger must be stable.
PicoScope's math channels can be used to apply a sliding-window filter to your signals. All four basic shapes of filter are available:
Most digital oscilloscopes gain their high sampling rates by interleaving multiple 8-bit ADCs. Despite careful design, the interleaving process introduces errors that always make the dynamic performance worse than the performance of the individual ADC cores.
The PicoScope 5000 Series scopes have a significantly different hardware architecture in which multiple high-resolution ADCs can be applied to the input channels in different time-interleaved and parallel combinations to boost either the sampling rate to 1 GS/s at 8 bits or the resolution to 16 bits at 62.5 MS/s.
For the first time in an oscilloscope you can reconfigure the hardware to optimize either for speed or resolution.
Some oscilloscopes struggle when you enable deep memory; the screen update rate slows and controls become unresponsive. PicoScope deep memory oscilloscopes avoid this limitation with use of a dedicated hardware acceleration engine. Its massively parallel design effectively creates the waveform image to be displayed on the PC screen inside the oscilloscope and allows the continuous capture and display to the screen of 2.5 billion samples every second. PicoScope oscilloscopes manage deep memory better than competing oscilloscopes, both PC-based and benchtop.
Hardware acceleration speeds up areas of oscilloscope operation such as allowing waveform update rates in excess of 170,000 waveforms per second and the segmented memory / rapid trigger modes. The hardware acceleration engine ensures that any concerns about the USB connection or PC processor performance being a bottleneck are eliminated.
The input impedance of a PicoScope is the impedance it presents to the oscilloscope probe, if one is used, or otherwise directly to the device under test. It is typically 1 MΩ in parallel with 10 to 15 pF. Some PicoScopes allow their their inputs to be individually switched to 50 Ω impedance, to allow proper termination of 50 Ω cables and sources.
I2C was developed by Philips as a low-cost way to connect peripheral chips in consumer electronics products and is widely adopted in embedded systems.
Many devices, including temperature sensors, control panels, microcontrollers, and single board prototyping systems incorporate multiple I2C interfaces for easy chip-to-chip and inter-module communications.
I2C waveforms can be decoded with PicoScope: From the "Tools" menu select "Serial Decoding" then "Create" and select I2C from the list of available protocols.
Jitter is uncertainty in the timing of a signal edge. The signal being measured by the oscilloscope may have jitter of its own, caused by unstable frequency, amplitude or pulse width. This is added to the oscilloscope’s intrinsic jitter caused by imperfections in its triggering and timing circuits. PicoScope 9000 Series scopes can display a histogram of edge timings, allowing accurate measurement of jitter.
PicoScope comes configured with the most useful keyboard shortcuts for operations like zoom, start/stop and buffer navigation. You can also define your own shortcuts for over 200 PicoScope commands, and load and save sets of shortcuts called keyboard maps. Additional, advanced keyboard maps for QWERTY and DVORAK keyboards are built in.
The PicoScope oscilloscope software offers a wide range of simple and advanced triggers for detecting and capturing elusive signals. Most of these trigger types are capable of monitoring only one signal at a time. Since many oscilloscopes have more than one input—up to eight channels as well as an EXT or AUX input on some models—PicoScope provides a special ‘Logic’ trigger type that can watch for combinations of up to four inputs.
The simplest way to monitor multiple inputs is to trigger when any one of them meets a specified condition. However, there are applications that require a more selective approach. For example, we might want to detect when both inputs meet specified conditions at the same time. PicoScope solves this problem by offering a list of logical functions for combining inputs.
If you plug in a PicoScope mixed-signal oscilloscope (MSO), the software will provide another triggering type called ‘Digital’. This behaves as a separate input to the Logic trigger function. For further information on the MSO Logic trigger, see the PicoScope 6 User’s Guide.
PicoScope for Linux is a powerful oscilloscope application that works with all PicoScope models. The most important features from PicoScope for Windows are included—scope, spectrum analyzer, advanced triggers, automated measurements, interactive zoom, persistence modes and signal generator control. More features are being added all the time.
Waveform captures can be saved for off-line analysis, and shared with PicoScope for Linux, PicoScope for Mac OS X, and PicoScope for Windows users, or exported in text, CSV and MathWorks MATLAB 4 formats.
Mask limit testing allows you to compare live signals against known good signals, and is designed for production and debugging environments. Simply capture a known good signal, draw a mask around it, and then attach the system under test. PicoScope will perform pass/fail testing, capture intermittent glitches, and can show a failure count and other statistics in the Measurements window.
Mask limit testing is available for both the oscilloscope and spectrum analyzer, allowing you automate finding problems in both the time and frequency domains.
The numerical and graphical mask editors can be used separately or in combination, allowing you to enter accurate mask specifications, modify existing masks, and import and export masks as files.
In addition to testing waveforms in the time domain mask limit testing can be applied to frequency domain signals.
On many oscilloscopes waveform math just means simple calculations such as A + B. With a PicoScope it means much, much more.
With PicoScope 6 you can select simple functions such as addition and inversion, or open the equation editor to create complex functions involving filters (low pass, high pass, band pass and band stop filters), trigonometry, exponentials, logarithms, statistics, integrals and derivatives.
Waveform math also allows you to plot live signals alongside historic peak, averaged or filtered waveforms. You can also use math for example to graph the changing duty cycle or frequency of your signal.
Making measurements in PicoScope is easy. A large number of measurements are possible thanks to the automated measurement system. Using the Measurements menu you can select what measurements you want PicoScope to make, and PicoScope will then automatically display a table of their values.
A type of digital oscilloscope that combines the basic functions of a 16-channel logic analyzer with the functionality of a 2- or 4-channel digital oscilloscope.
PicoScope for Mac OS X is a powerful oscilloscope application that works with all PicoScope models. The most important features from PicoScope for Windows are included—scope, spectrum analyzer, advanced triggers, automated measurements, interactive zoom, persistence modes and signal generator control. More features are being added all the time.
Waveform captures can be saved for off-line analysis, and shared with PicoScope for Mac OS X, PicoScope for Linux, and PicoScope for Windows users, or exported in text, CSV and MathWorks MATLAB 4 formats.
Noise is any unwanted signal added to a wanted signal. These unwanted signals arise from a variety of sources which may be considered in one of two main categories:
Interference arises in communication systems from many sources due to crosstalk: 50/60 Hz supplies (causing hum) and harmonics, switched mode power supplies, thyristor circuits, ignition (car spark plugs) motors, etc.
Naturally occurring external noise sources include atmosphere disturbance (e.g. electric storms, lighting, ionospheric effect), and so-called sky noise or cosmic noise.
Thermal noise is electronic noise generated by the thermal agitation of the charge carriers inside an electrical conductor. Thermal noise in a resistor is of a type called white noise, meaning that its power spectral density is nearly constant throughout the frequency spectrum.
PicoScope has a white noise generator to help circuit designers evaluate noise immunity in their designs.
PicoScope enables sharing of instrument settings, waveforms and measurement data with PSDATA files that can be saved by a user and loaded by other users running PicoScope 6 on their own PC.
PicoScope 6 software is free of charge and can be run on Microsoft Windows-based PCs and tablets, plus Linux and Apple Mac OS X platforms. Off-line analysis delivers the full visualization, measurement, and documentation capabilities found on PicoScope oscilloscopes to engineers who are doing their work away from the lab.
To speed up analysis and and to help get started at the right place, the PSDATA file loads the acquired waveform(s) and restores all the instrument display and measurement settings. Powerful visualizations include multi-viewport waveform displays with interactions for zooming, rulers, and notes, along with advanced waveform math.
PSDATA files can be saved with any PicoScope 2000, 3000, 4000, 5000 or 6000 Series oscilloscope.
Advanced display modes allow you to collect thousands of waveforms per second. New or more frequent data can be displayed in a brighter color or shade. This makes it easy to see glitches and dropouts and to estimate their relative frequency. Choose between analog persistence, digital color, fast or custom display modes.
Phase rulers (called rotation rulers in PicoScope Automotive) are a set of lines that can be drawn over a scope trace to help measure phase angles. This is particularly useful for analyzing rotating machines and AC power waveforms.
Place two phase rulers at the start and end of a cyclic waveform. Next, drag one or two time rulers onto the scope view, and PicoScope will then display time ruler measurements as phase angles as well as times.
Optionally, PicoScope can draw additional rulers to divide the waveform into equal partitions (for example, four partitions of 90 degrees each).
To minimize capacitive loading on the device under test, most probes use a 10:1 attenuator. This can often be adjusted, or compensated, to improve the frequency response.
The probe should be adjusted to compensate for the specific oscilloscope channel that you are using. To do this connect the probe to a 1 kHz square wave calibration source and use a non-magnetic adjustment tool to adjust the compensation network to obtain a waveform display that has flat tops with no overshoot or rounding.
An uncompensated probe can lead to measurement errors, especially in measuring pulse rise or fall times.
For more information, see the application note "How to compensate 10:1 oscilloscope probes".
Rapid trigger mode allows you to segment the PicoScope buffer memory and make acquisitions to successive segments with minimum delay between each acquisition. As the scope does not communicate with the PC between captures, this reduces the gap from milliseconds to less than a few microseconds, at the fastest sampling rates.
After capture of the number of requested segments set by the user the acquisition process halts and you can scroll through captured waveforms in the usual way using the buffer navigation buttons.
With PicoScope you can display stored waveforms alongside live traces. You can apply all the same functions to the reference waveforms as you can to live waveforms, such as automatic and manual measurements, scaling and offset, and exporting to a file. Reference waveforms are especially useful for production testing and diagnostics, where they allow you to compare waveforms from the equipment under test with known good waveforms.
You can also shift the timebase of a reference waveform relative to live waveform data: click the color-coded axis control button at the bottom of the y axis for the reference waveform and adjust the box marked ‘Delay’.
Resolution enhancement is a technique for increasing the effective vertical resolution of the scope at the expense of high-frequency detail. It is useful for resolving small signal details and for reducing unwanted noise. Unlike waveform averaging it can be used on single-shot signals.
RS-232 is a standard for serial data communication first defined in 1962 by the Electronic Industries Alliance for use with data communication devices such as Teletypewriters. Later, personal computers and other devices made use of the RS-232 standard for connection to peripheral devices such as modems, mice, keyboards, etc. In recent years RS-232 has become increasingly displaced by USB in modern PC’s, though the standard, and many variants, are still widely used in industrial machines, networking equipment and scientific instruments.
Scope view is the default mode of PicoScope. All the software's basic and advanced features can be accessed from here. As you can see, most of the display is dedicated to the most important feature: your signal.
The top toolbars reveal yet more functions including spectrum and persistence modes, the buffer navigator and zoom tools, channel setup, custom probes and the signal generator/arbitrary waveform generator.
SENT (Single Edge Nibble Transmission), SAE standard J2716, is a one way, point-to-point protocol for transmission of signal values from sensors to a controller. It is used mainly in automotive applications and enables reliable transmission of high-resolution data with lower cost than standards such as CAN, and higher bit rate than LIN.
Data is transmitted in units of 4 bits (1 nibble), for which the time is measured between falling edges (single edge) of the modulated signal. Primary data is normally transmitted in what is called the “Fast channel” with the option to simultaneously send secondary data in the “Slow channel.”
Fast channel transmission typically has two 12-bit data words transmitted in each message frame, although other options are also possible, such as 16 bits for signal 1 and 8 bits for signal 2.
Slow channel data is sent two bits at a time within the standard SENT message frame. So for each fast channel message frame the transmitter can also include two bits of slow channel data: bit 3 and bit 2 of the status nibble. The purpose of the slow channel feature is to allow up to 32 slow channel messages per serial message cycle to be transmitted with minimal impact on the primary sensor data. Slow channel messages can be used to continually monitor information such as temperature, diagnostics and production codes, which either do not change or change at a slower rate than the primary sensor data.
SENT data format is determined by what is best suited to the application. Once the format and data set have been selected, it is usually fixed in the design or configured with nonvolatile memory so that the data is continually transmitted on power up.
PicoScope can decode 1-Wire, ARINC 429, CAN, DCC, DMX512, Ethernet 10Base-T and 100Base-TX, FlexRay, I²C, I²S, LIN, PS/2, SENT, SPI, UART (RS-232 / RS-422 / RS-485), and USB protocol data as standard, with more protocols in development, and available in the future with free-of-charge software upgrades.
In graph format shows the decoded data (in hex, binary, decimal or ASCII) in a data bus timing format, beneath the waveform on a common time axis, with error frames marked in red. These frames can be zoomed to investigate noise or signal integrity issues.
In table format shows a list of the decoded frames, including the data and all flags and identifiers. You can set up filtering conditions to display only the frames you are interested in or search for frames with specified properties. The statistics option reveals more detail about the physical layer such as frame times and voltage levels. PicoScope can also import a spreadsheet to decode the data into user-defined text strings.
A signal generator is an invaluable piece of test equipment. The output from a signal generator is a repeating waveform whose characteristics are set by the user. Signal generators can be used for research and development purposes, along with the servicing and repair of electronic equipment.
Most PicoScope PC oscilloscopes include an integrated signal generator. The signal generator is controlled using the PicoScope software.
Most oscilloscopes are built down to a price. PicoScopes are built up to a specification.
Careful front-end design and shielding reduces noise, crosstalk and harmonic distortion. Years of oscilloscope design experience can be seen in improved bandwidth flatness and low distortion.
We are proud of the dynamic performance of our products and, unlike most oscilloscope manufacturers, we publish our specifications in detail. The result is simple: when you probe a circuit, you can trust in the waveform you see on the screen.
In addition to the PicoScope application software, the PicoScope Software Development Kit (SDK) is available free of charge.
The SDK allows you to write your own software and includes drivers for Microsoft Windows, Apple Mac (OS X) and Linux (including Raspberry Pi and Beaglebone).
Example code shows how to interface to third-party software packages such as Microsoft Excel, National Instruments LabVIEW and MathWorks MATLAB and programming languages including:
The drivers support USB data streaming, a mode that captures gap-free continuous data over USB direct to the PC’s RAM or hard disk at rates of up to 156.25 MS/s for USB 3.0 devices. Capture size is limited only by available PC storage. Sampling rates in streaming mode are subject to PC specifications, product specifications and application loading.
The spectrum view plots amplitude vs frequency and is ideal for finding noise, crosstalk or distortion in signals. The spectrum analyzer in PicoScope is of the Fast Fourier Transform (FFT) type which, unlike a traditional swept spectrum analyzer, can display the spectrum of a single, non-repeating waveform.
A full range of settings gives you control over the number of spectrum bands (FFT bins), window types, scaling (including log/log) and display modes (instantaneous, average, or peak-hold).
You can display multiple spectrum views alongside oscilloscope views of the same data. A comprehensive set of automatic frequency-domain measurements can be added to the display, including THD, THD+N, SNR, SINAD and IMD. A mask limit test can be applied to a spectrum and you can even use the AWG and spectrum mode together to perform swept scalar network analysis.
SPI (Serial Peripheral Interface) bus was originally developed by Motorola for use with their microcontrollers. Due to the simplicity of the bus, other manufacturers adopted it and it has become widely available in components used in embedded system designs. It is commonly used for chip-to-chip communications between a CPU and keyboard, display, ADCs and DACs, real-time clocks, EEPROM, SD and other memory devices.
SPI is a synchronous bus with four lines: Data - master output/slave input (MOSI) and master input/slave output (MISO), clock (SCLK), and slave select (SS or CS). SPI is a full duplex standard, meaning signals can be transmitted in both directions simultaneously, with data rates from a few Mb/s to tens of Mb/s.
Devices communicate using a master-slave architecture with a single master. The master device initiates the frame for reading and writing. Multiple slave devices can be addressed with individual slave select lines.
SPI waveforms can be decoded with PicoScope: From the Tools menu select Serial Decoding then Create and select SPI from the list of available protocols.
In this mode, data is passed directly to the host PC with buffering provided by the PicoScope internal buffer memory. This enables long periods of slow data collection for chart recorder and data-logging applications as well as fast USB streaming.
In PicoScope 6, the maximum number of samples that can be collected for each channel is 100 million. The Software Development Kit (SDK) allows unlimited data collection.
With faster scopes, both the speed of the USB connection and the amount of on-scope buffer memory may limit the fastest usable sampling rate.
Use streaming mode for:
The PicoScope 6 software and PicoScope oscilloscopes have a number of advanced trigger types that enable you to capture a stable waveform even with complex signals. This makes them ideal for troubleshooting glitches, timing violations, overvoltages and dropouts in analog and digital circuits.
PicoScope lets you optionally share usage statistics with Pico to help us improve our software. Usage statistics help us prioritize features and device support. These usage statistics are anonymized and do not contain any personally identifiable information. Usage statistics include the following:
USB (Universal Serial Bus) is widely adopted in today’s personal computers and tablets for communication and power to printers, scanners, keyboard, mice, memory devices and many other peripherals. It is also used for chip-to-chip and module-to-module communication in many other types of electronic devices and embedded systems. The USB specification has evolved several times since its launch in 1996.
Most of the USB devices being used today conform to the USB 2.0 specification.
The USB 3.0 “SuperSpeed” specification was released in 2008 with 5 Mbit/s data rate plus backward compatibility with USB 2.0 devices. USB 3.1, released in 2013, introduced a faster transfer mode called "SuperSpeed USB 10 Gbit/s" and backwards compatible with USB 3.0 and USB 2.0.
USB configurations have a single host (Master) controller that controls all bus traffic with up to 127 devices. Optional hubs can be used to expand the bus.
USB 2.0 transfers are negotiated starting at full-speed and then transition to high speed if both devices will support it. Speed of a USB 2.0 bus is limited by the slowest device connected to the host controller. With SuperSpeed USB, two host controllers are used: one for SuperSpeed USB devices and one for USB 2.0 devices.
USB 2.0 waveforms can be decoded with PicoScope: From the Tools menu select Serial Decoding then Create and select USB from the list of available protocols.
PicoScope oscilloscopes can be powered from a variety of sources. Many models can be powered directly from the USB connection, while the highest-performance models require an external AC adaptor.
Some models can operate with USB power with two channels turned on, but require an AC adaptor to support four-channel operation.
When you plug in a flexible-power scope, PicoScope shows you a power options panel like this. The range of options depends on the capabilities of the scope.
Vibration in mechanical systems, particularly with rotating machinery, can be very problematic, creating unwanted noise or introducing stresses that can lead to catastrophic failures. Analysing vibration can help to identify root causes and allow corrections to be made to improve reliability.
PicoScope 4000 Series high-resolution, and PicoScope 5000 Series flexible resolution oscilloscopes can be used to perform simple and effective vibration testing and analysis.
An important specification to understand when evaluating oscilloscope performance is the waveform update rate, which is expressed as waveforms per second (wfms/s). While the sample rate indicates how frequently the oscilloscope samples the input signal within one waveform, or cycle, the waveform capture rate refers to how quickly an oscilloscope acquires waveforms.
Oscilloscopes with high waveform capture rates provide better visual insight into signal behavior and dramatically increase the probability that the oscilloscope will quickly capture transient anomalies such as jitter, runt pulses and glitches – that you may not even know exist.
PicoScope deep memory oscilloscopes use hardware acceleration to achieve over 100,000 wfms/s.
PicoScope is the standard in PC Oscilloscope software – a complete test and measurement lab in one easy-to-use application.
PicoScope for Windows works with all PicoScope models. Oscilloscope, spectrum analyzer, advanced triggers, automated measurements, interactive zoom, persistence modes, maths channels, mask testing, serial bus decoding and analysis, and signal generator control are all included as standard. More features are being added all the time.
In PicoScope, waveform averaging is a mathematical function that computes the average of a sequence of waveforms. This is useful for removing noise from a repetitive signal. The result of averaging is a cleaner picture with the same frequency resolution as the original capture but with increased vertical resolution.
The example opposite shows the result of waveform averaging on a noisy square wave. The lower waveform is the raw signal. The upper waveform is the cleaned-up signal at the same scale factor. Despite the reduction in noise this waveform has a large amount of high-frequency detail, giving us an accurate picture of the original pulse shape.
The waveform buffer toolbar at the top of the window shows that PicoScope captured 32 waveforms to create the averaged result. It is also possible to run PicoScope in a continuous averaging mode, in which the displayed waveform is the time-weighted average of all previous waveforms.
Ever spotted a glitch on a waveform, but by the time you’ve stopped the scope it has gone? With PicoScope you no longer need to worry about missing glitches or other transient events. PicoScope can store the last ten thousand waveforms in its circular waveform buffer.
When the trace length is set to be shorter than the scope’s memory, PicoScope will automatically configure the memory as a circular buffer storing as many as ten thousand waveforms.
The buffer navigator provides an efficient way of navigating and searching through waveforms effectively letting you turn back time. Tools such as mask limit testing can also be used to scan through each waveform in the buffer looking for mask violations.
An XY view, in its simplest form, shows a graph of one channel plotted against another. XY display mode is useful for showing relationships between periodic signals (using Lissajous figures) and for plotting I–V (current-voltage) characteristics of electronic components.
Many PicoScope oscilloscopes have deep buffer memory, which allows them to sustain high sampling rates across long timebases. For example, with a 512 MS buffer the PicoScope 3206D and 3406D models can sample at 1 GS/s all the way down to 50 ms/div to give a total capture time of 500 ms. Powerful tools such as the zoom function enable you to navigate and examine all the waveform data in detail. The zoom overview window allows you to easily control the size and location of the zoom area by just clicking and dragging.
The PicoScope multi-viewport display system builds on this by allowing you to see an overview of the captured waveform in one viewport and, simultaneously, detailed views of different parts of the waveform in other viewports.