Profile of an oscilloscope performing lab measurements of all kinds

Article By : Tim Paasch-Colberg

The oscilloscope features extensive analysis functions and a new user concept optimized for practical measurements on a full HD touchscreen.

Many improvements in the RTO6 Series from Rohde & Schwarz arose from customer suggestions to make their work easier with the oscilloscope. For a start, the large 15.6-inch high definition (HD) touchscreen and the new graphical user interface maximize the display area for measurement signals. Next, the SmartGrid technology allows users to drag and drop signals on the screen as desired (Figure 1).

Figure 1 All settings can be configured on the 15.6-inch full HD touchscreen with just a few clicks. Source: Rohde & Schwarz

Frequently used measurement functions and configurations can be pinned to a toolbar at the top of the touchscreen. Acting as a main menu, the app cockpit provides a one-tap location to access all of the available oscilloscope applications. Even with the oscilloscope’s user menu opened, the user can see nearly all of the recently displayed waveforms (Figure 2).

Figure 2 Despite fast access to all functions through a compact main menu and several toolbars, the signals and measurement results are always visible on the large screen. Source: Rohde & Schwarz

A low-noise front-end and a low-distortion A/D converter specially developed for the oscilloscope form the basis for an accurate analysis of signal details. Additionally, with the HD mode digital filter, the oscilloscope achieves a maximum vertical resolution of 16-bit and a lower noise floor, allowing very small signals to be displayed with high resolution. Signal integrity of oscilloscope is clearly demonstrated by the spurious-free dynamic range (SFDR) of 68 dB and the overall effective number of bits (ENOB) of 9.4. The patented digital trigger with adjustable hysteresis allows the high-resolution measurement of signals to be fully utilized.

Signal processing in the oscilloscope is optimized by an ASIC. This allows the oscilloscope to achieve an unmatched real-time acquisition rate of 1 million waveforms per second, enabling users to detect even sporadic signal anomalies. Rohde & Schwarz has additionally integrated a highly responsive acquisition memory as standard in the new oscilloscope with a memory depth of 200 million measurement points (200 Mpoints) per channel, expandable to 2 Gpoints. A frequency stable oven-controlled crystal oscillator (OCXO) serving as an accurate clock source is included in the scope of delivery, giving the oscilloscope a very precise timebase.

The zone trigger function, also included as standard in the oscilloscope, is unique in the market. It allows the user to draw up to eight zones on the touchscreen and link them to logic functions that trigger the instrument (Figure 3). These fully independent zones can be located in the time domain of the measured waveforms or in their frequency domain, which means in the calculated spectrum (FFT). In addition, mask testing detects signal faults in the defined tolerance limits. The high acquisition rate of the oscilloscope is also especially helpful, for example, for performing eye diagram tests with good measurement statistics in a short time.

Figure 3 Using the standard integrated zone trigger, the user can define up to eight resolution-sensitive zones in the time or frequency domain and logically link them to math functions, even across channels. Source: Rohde & Schwarz

Below is a detailed look on what engineers can do with this oscilloscope.

  1. Measurement functions for a variety of applications

The oscilloscope comes with a new operating concept, a larger display and a comprehensive range of software options, providing fast, detailed insights into electronic designs. Optional functions for special applications can be activated by user-entered keycodes. That makes the oscilloscope suitable for a wide variety of applications, including automotive, communications, power electronics and EMI debugging as well as testing digital bus and interface standards.

  1. Spectrum analysis with zone trigger for EMI measurements

Electromagnetic interference (EMI) can be detected very quickly and easily using spectrum analysis (Figure 4). Users can perform up to eight spectrum analyses in parallel with individual selection of the center frequency, frequency range, and resolution bandwidth. For each analysis, the analyzed section of the measured waveform can be restricted in the time domain with gated FFT.

Figure 4 EMI debugging on four channels with two domains; it’s often helpful to be able to compare the time-domain and spectral-domain behavior of a device under test (DUT). Source: Rohde & Schwarz

In addition, zones can be defined in both the time and frequency domains using the zone trigger function. Zones activate a trigger when a signal either intersects or does not intersect the zone. This enables precise identification of spurious signals. The user can also correlate events detected by the instrument with the time domain signal to simplify searching for the cause.

  1. Tracking power signal details

A separate software option with automatic measurement routines is available for characterizing power electronics. This software supports the analysis of turn on/off behavior, internal transfer function, safe operating area (SOA), output signal quality, and switching losses. It allows users to test power transistors in line with common international test standards.

  1. Accurate power integrity measurements on embedded designs

Power integrity measurements enable developers to determine, for example, whether fast clock and data edges are coupled into sometimes quite low supply voltage of a highly sensitive component. For this, the supply noise and ripple must be measured with high precision. These measurements are possible with an RTO6 oscilloscope. Users can employ special, extremely low-noise ZPR power rail probes with 1:1 attenuation factor and a large offset compensation range. With these probes, the oscilloscope can reliably track down deviations and display them with high resolution.

  1. Fault localization in signal paths

The oscilloscope can be equipped with a differential pulse source. This option enables users to locate faults in signal paths such as PCB traces, cables or connectors using time domain reflectometry (TDR) and time domain transmissometry (TDT).

  1. Capturing and analyzing bus signals with a large acquisition memory

Protocol analysis options can be used for testing the correct transmission of bus signals. These options are available for many serial buses, including DDR3/4, USB and SPI/CAN/LIN. Analysis software is even available for Automotive Ethernet transmissions (Figure 5). The large high-speed acquisition memory—with a standard capacity of 200 Mpoints per channel, expandable to as much as 2 Gpoints—allows long signal sequences to be used for analysis.

Figure 5 The lab oscilloscope can be used to analyze many common serial bus signals, as well as Automotive Ethernet signals such as 1000BASE-T1. Source: Rohde & Schwarz

  1. Compliance measurements for high-speed data interfaces

The oscilloscope can also be used for automated compliance testing of various data interfaces with dedicated software options. The associated ScopeSuite compliance test software runs either on the oscilloscope or on a separate PC. It controls the measurement settings and test sequences on the oscilloscope and guides the user through the test sequences. Detailed instructions make it easy to correctly connect the oscilloscope and probes to the test fixture and DUT.

Rohde & Schwarz offers standard-compliant test fixtures for a variety of transmission interfaces. The ScopeSuite software also includes a report tool with an extensive range of functions for the documentation of measurement results.

  1. Detailed jitter analysis

The higher the data rate, the greater the impact of jitter on signal transmission. With its very precise clock signals, the integrated OCXO enables accurate jitter measurements, which the instrument can visualize in various forms such as eye diagrams and histograms. The jitter analysis software also analyzes the individual jitter components using a unique decomposition algorithm, giving the user quick feedback on signal quality and any error sources.

  1. I/Q interface for analysis of broadband RF signals

The oscilloscope also has an option for real-time conversion of modulated RF signals into digital I/Q signals. For further processing of the I/Q data, the user needs either the VSE vector signal explorer software from Rohde & Schwarz or another tool such as MATLAB. In combination with a harmonic mixer, the oscilloscope with a maximum measurement bandwidth of 6 GHz can even perform detailed analysis of broadband transmission signals such as OFDM, radar, and 5G MIMO.

The FS-Zxx harmonic mixer brings the RF carrier frequency in the range of 50 GHz to 110 GHz down to the measurement range of the oscilloscope. Here, the VSE software offers a wide range of analysis tools for a variety of pulsed and analog modulated signals as well as I/Q signals, including multiple WLAN and mobile communications standards.

Technical characteristics optimized

Like its predecessors, the R&S RTO6 oscilloscope series—now in the third generation—has been optimized for maximum user convenience. Now that technical characteristics such as low-noise frontends and A/D converters have largely been optimized, users primarily receive added value in the form of application-specific software functions and a well-conceived graphical user interface. A key factor for all-day stress-free use in the lab is quiet operation. The barely audible oscilloscope fulfills all expectations in this regard.

This article was originally published on EDN.

Tim Paasch-Colberg is product manager for oscilloscopes at Rohde & Schwarz.


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