Mixed Domain Oscilloscope with (4) 1 GHz analog channels, (16) digital channels, and (1) 6 GHz RF input

Introducing the Mixed Domain Oscilloscope

Introducing the world's first and only oscilloscope with a built-in spectrum analyzer. For the first time ever, you can capture time-correlated analog, digital, and RF signals for a complete system view of your device. See both the time and frequency domain in a single glance. View the RF spectrum at any point in time to see how it changes over time or with device state. Solve the most complicated design issues, quickly and efficiently, with an oscilloscope as integrated as your design.

Based on the industry-standard MSO4000B Oscilloscope Series, you can now use your tool of choice, the oscilloscope, to look at the frequency domain rather than having to find and re-learn a spectrum analyzer. However, the power of the MDO4000 Series goes well beyond simply observing the frequency domain as you would on a spectrum analyzer. The real power is in its ability to correlate events in the frequency domain with the time domain phenomena that caused them. When both the RF channel and any analog or digital channels are on, the oscilloscope display is split into two views. The upper half of the display is a traditional oscilloscope view of the Time Domain. The lower half of the display is a Frequency Domain view of the RF input. Note that the Frequency Domain view is not simply an FFT of the analog or digital channels in the instrument, but is the spectrum acquired from the RF input. Another key difference is that with traditional oscilloscope FFTs, you can typically either get the desired view of the FFT display, or the desired view of your other time domain signals of interest, but never both at the same time. This is because traditional oscilloscopes only have a single acquisition system with a single set of user settings such as record length, sample rate, and time per division that drive all data views. But with the MDO4000 Series, the RF input has its own acquisition system that is independent, but time correlated, to the analog and digital channel acquisition systems. This allows each domain to be configured optimally, providing a complete time correlated system view of all analog, digital, and RF signals of interest. The spectrum shown in the Frequency Domain view is taken from the period of time indicated by the short orange bar in the time domain view – known as the Spectrum Time. With the MDO4000 Series, Spectrum Time can be moved through the acquisition to investigate how the RF spectrum changes over time. And this can be done while the oscilloscope is live and running or on a stopped acquisition.

The upper half of the MDO4000 Series display shows the Time Domain view of the analog and digital channels, while the lower half shows the Frequency Domain view of the RF channel. The orange bar - Spectrum Time - shows the period of time used to calculate the RF spectrum.

Figures 1 through 4 show a simple everyday application – tuning of a PLL. This application illustrates the powerful connection between the time domain and the frequency domain that the MDO4000 Series provides. With its wide capture bandwidth and ability to move Spectrum Time throughout the acquisition, this single capture includes the same spectral content as approximately 1,500 unique test setups and acquisitions on a traditional spectrum analyzer. For the first time ever, correlating events, observing interactions, or measuring timing latencies between the two domains is exceptionally easy, giving you quick insight to your design’s operation.

Figure 1 - Time and Frequency Domain view showing the turn-on of a PLL. Channel 1 (yellow) is probing a control signal that enables the VCO. Channel 2 (cyan) is probing the VCO tune voltage. The SPI bus which is programming the PLL with the desired frequency is probed with three digital channels and automatically decoded. Notice Spectrum Time is placed after the VCO was enabled and coincident with the command on the SPI bus telling the PLL the desired frequency.

Visualizing changes in your RF signal
The time domain graticule on the MDO4000 Series display provides supportfor three RF time domain traces that are derived from the underlying I and Qdata of the RF input including:

• Amplitude - The instantaneous amplitude of the RF input vs. time
• Frequency - The instantaneous frequency of the RF input, relative to the center frequency vs. time
• Phase - The instantaneous phase of the RF input, relative to the center
• frequency vs. time

Each of these traces may be turned on and off independently, and all three
may be displayed simultaneously. RF time domain traces make it easy to
understand what's happening with a time-varying RF signal.

The orange waveform in the Time Domain view is the frequency vs. time trace derived from the RF input signal. Notice that Spectrum Time is positioned during a transition from the highest frequency to the lowest frequency, so the energy is spread across a number of frequencies. With the frequency vs. time trace, you can easily see the different frequency hops, simplifying characterization of how the device switches between
frequencies.

Fast and accurate spectral analysis

When using the RF input by itself, the MDO4000 Series display becomes a full-screen Frequency Domain view.

Key spectral parameters such as Center Frequency, Span, Reference Level, and Resolution Bandwidth are all adjusted quickly and easily using the dedicated front-panel menus and keypad.

Advanced triggering with RF, analog, and digital channels

In order to deal with the time-varying nature of modern RF applications, the MDO4000 Series provides a triggered acquisition system that is fully integrated with the RF, analog, and digital channels. This means that a single trigger event coordinates acquisition across all channels, allowing you to capture a spectrum at the precise point in time where an interesting time domain event is occurring. A comprehensive set of time domain triggers are available, including Edge, Sequence, Pulse Width, Timeout, Runt, Logic, Setup/Hold Violation, Rise/Fall Time, Video, and a variety of parallel and serial bus packet triggers. In addition, you can trigger on the power level of the RF input. For example, you can trigger on your RF transmitter turning on.

The optional MDO4TRIG application module provides advanced RF triggering. This module enables the RF input power level to be used as a source for Sequence, Pulse Width, Timeout, Runt, and Logic trigger types. For example, you can trigger on a RF pulse of a specific length or use the RF channel as an input to a logic trigger, enabling the oscilloscope to trigger only when the RF is on while other signals are active.

Intelligent, efficient markers

In a traditional spectrum analyzer, it can be a very tedious task to turn on and place enough markers to identify all your peaks of interest. The MDO4000 Series makes this process far more efficient by automatically placing markers on peaks that indicate both the frequency and the amplitude of each peak. You can adjust the criteria that the oscilloscope uses to automatically find the peaks.

The highest amplitude peak is referred to as the reference marker and is shown in red. Marker readouts can be switched between Absolute and Delta readouts. When Delta is selected, marker readouts show each peak's delta frequency and delta amplitude from the reference marker.

Two manual markers are also available for measuring non-peak portions of the spectrum. When enabled, the reference marker is attached to one of the manual markers, enabling delta measurements from anywhere in the spectrum. In addition to frequency and amplitude, manual marker readouts also include noise density and phase noise readouts depending on whether Absolute or Delta readouts are selected. A "Reference Marker to Center" function instantly moves the frequency indicated by the reference marker to center frequency.

Automated peak markers identify critical information at a glance. As shown here, the five highest amplitude peaks that meet the threshold and excursion criteria are automatically marked along with the peak's frequency and amplitude.

Spectrogram

The MDO4000 Series includes a spectrogram display which is ideal for monitoring slowly changing RF phenomena. The x-axis represents frequency, just like a typical spectrum display. However, the y-axis represents time, and color is used to indicate amplitude.

Spectrogram slices are generated by taking each spectrum and "flipping it up on its edge" so that it's one pixel row tall, and then assigning colors to each pixel based on the amplitude at that frequency. Cold colors (blue, green) are low amplitude and hotter colors (yellow, red) are higher amplitude. Each new acquisition adds another slice at the bottom of the spectrogram and the history moves up one row. When acquisitions are stopped, you can scroll back through the spectrogram to look at any individual spectrum slice.

Spectrogram display illustrates slowly moving RF phenomena. As shown here, a signalthat has multiple peaks is being monitored. As the peaks change in both frequency andamplitude over time, the changes are easily seen in the Spectrogram display.

Triggered versus Free Run operation

When both the time and frequency domains are displayed, the spectrum shown is always triggered by the system trigger event and is time correlated with the active time-domain traces. However, when only the frequency domain is displayed, the RF input can be set to Free Run. This is useful when the frequency domain data is continuous and unrelated to events occurring in the time domain.

Ultra-wide capture bandwidth

Today's wireless communications vary significantly with time, using sophisticated digital modulation schemes and, often, transmission techniques that involve bursting the output. These modulation schemes can have very wide bandwidth as well. Traditional swept or stepped spectrum analyzers are ill equipped to view these types of signals as they are only able to look at a small portion of the spectrum at any one time.

The amount of spectrum acquired in one acquisition is called the capture bandwidth. Traditional spectrum analyzers sweep or step the capture bandwidth through the desired span to build the requested image. As a result, while the spectrum analyzer is acquiring one portion of the spectrum, the event you care about may be happening in another portion of the spectrum. Most spectrum analyzers on the market today have 10 MHz capture bandwidths, sometimes with expensive options to extend that to 20, 40, or even 140 MHz in some cases.

In order to address the bandwidth requirements of modern RF, the MDO4000 Series provides ≥1 GHz of capture bandwidth. At span settings of 1 GHz and below, there is no requirement to sweep the display. The spectrum is generated from a single acquisition, thus guaranteeing you'll see the events you're looking for in the frequency domain.

Spectrum traces

The MDO4000 Series offers four different traces or views of the RF input including Normal, Average, Max Hold, and Min Hold. You can set the detection method used for each trace type independently or you can leave the oscilloscope in the default Auto mode that sets the detection type optimally for the current configuration. Detection types include +Peak, - Peak, Average, and Sample.

RF measurements

The MDO4000 Series includes three automated RF measurements - Channel Power, Adjacent Channel Power Ratio, and Occupied Bandwidth. When one of these RF measurements is activated, the oscilloscope automatically turns on the Average spectrum trace and sets the detection method to Average for optimal measurement results.

Advanced RF measurements

The MDO4000 can save the baseband I and Q data from RF acquisitions to a .TIQ file. These files can then be imported into Tektronix' SignalVu-PC and RSAVu analysis packages for further modulation analysis on many wireless standards.

RF probing
Signal input methods on spectrum analyzers are typically limited to cabled connections or antennas. But with the optional TPA-N-VPI adapter, any active, 50 Ω TekVPI probe can be used with the RF input on the MDO4000Series. This enables additional flexibility when hunting for noise sources and enables easier spectral analysis by using true signal browsing on an RF input.

In addition, an optional preamplifier accessory assists in the investigation of lower-amplitude signals. The TPA-N-PRE preamplifier provides 12 dB nominal gain across the 9 kHz - 6 GHz frequency range.

Built on the award-winning MSO4000B Series of Mixed Signal Oscilloscopes

The MDO4000 Series provides you with the same comprehensive set of features available in the MSO4000B Mixed Signal Oscilloscope Series. This robust set of tools will help you speed through every stage of debugging your design - from quickly discovering an anomaly and capturing it, to searching your waveform record for the event and analyzing its characteristics and your device's behavior.

Discover

To debug a design problem, first you must know it exists. Every design engineer spends time looking for problems in their design, a timeconsuming and frustrating task without the right debug tools. The industry’s most complete visualization of signals provides fast insight into the real operation of your device. A fast waveform capture rate – greater than 50,000 waveforms per second – enables you to see glitches and other infrequent transients within seconds, revealing the true nature of device faults. A digital phosphor display with intensity grading shows the history of a signal’s activity by intensifying areas of the signal that occur more frequently, providing a visual display of just how often anomalies occur.

Capture

Discovering a device fault is only the first step. Next, you must capture the event of interest to identify root cause.

Accurately capturing any signal of interest begins with proper probing. Lowcapacitance probes are included with the oscilloscope, one for each analog channel. These industry-first high-impedance passive voltage probes have less than 4 pF of capacitive loading to minimize the affect of the probe on your circuit's operation, offering the performance of an active probe with the flexibility of a passive probe.

A complete set of triggers - including runt, timeout, logic, pulse width/glitch, setup/hold violation, serial packet, and parallel data - help you quickly find your event. With up to a 20M point record length, you can capture many events of interest, even thousands of serial packets, in a single acquisition for further analysis while maintaining high resolution to zoom in on fine signal details.

From triggering on specific packet content to automatic decode in multiple data formats, the oscilloscope provides integrated support for the industry's broadest range of serial buses - I2C, SPI, USB, Ethernet, CAN, LIN, FlexRay, RS-232/422/485/UART, MIL-STD-1553, and I2S/LJ/RJ/TDM. The ability to decode up to four serial and/or parallel buses simultaneously means you gain insight into system-level problems quickly.

To further help troubleshoot system-level interactions in complex embedded systems, the oscilloscope offers 16 digital channels in addition to its analog channels. Since the digital channels are fully integrated into the oscilloscope, you can trigger across all input channels, automatically time correlating all analog, digital, serial, and RF signals. The MagniVu™ highspeed acquisition on these channels enables you to acquire fine signal detail (up to 60.6 ps resolution) around the trigger point for precision timing measurements. MagniVu is essential for making accurate timing measurements for setup and hold, clock delay, signal skew, and glitch characterization.

Search

Finding your event of interest in a long waveform record can be time consuming without the right search tools. With today’s record lengths pushing beyond a million data points, locating your event can mean scrolling through thousands of screens of signal activity. The innovative Wave Inspector® controls give you the industry’s most comprehensive search and waveform navigation capability. These controls speed panning and zooming through your record. With a unique forcefeedback system, you can move from one end of your record to the other in just seconds. User marks allow you to mark any location that you may want to reference later for further investigation. Or, automatically search your record for criteria you define. Wave Inspector will instantly search your entire record, including analog, digital, serial-bus, and RF-versus-time data.

Along the way it will automatically mark every occurrence of your defined event so you can quickly move between events.

Analyze

Verifying that your prototype’s performance matches simulations and meets the project’s design goals requires analyzing its behavior. Tasks can range from simple checks of rise times and pulse widths to sophisticated power loss analysis and investigation of noise sources. The oscilloscope offers a comprehensive set of integrated analysis tools including waveform- and screen-based cursors, automated measurements, advanced waveform math including arbitrary equation editing, spectral math, FFT analysis, and trend plots for visually determining how a measurement is changing over time. Specialized application support for serial bus analysis, power supply design, and video design and development is also available. For extended analysis, National Instrument’s LabVIEW SignalExpress® Tektronix Edition provides over 200 built-in functions including time and frequency domain analysis, limit testing, data logging, and customizable reports.