Scope and spectrum analyzer combination provides time correlated analog, digital and RF signals -

Scope and spectrum analyzer combination provides time correlated analog, digital and RF signals


To address its belief that more than 60 percent of oscilloscope users also use a spectrum analyzer to troubleshoot embedded system designs with integrated wireless functionality Tektronix Inc. has developed the mixed domain oscilloscope (MDO).

The MDO4000 enables work in both the time and frequency domain to provide the capture time-correlated analog, digital and RF signals for a complete system view.

A multi-year research and development project by Tektronix, which has seen the company file for 26 patents that are pending, has overcome the obstacles inherent in integrating the time and frequency domains in a single instrument.

The move has been driven by wireless becoming more common which means that design engineers must change from ether being a mixed signal/digital engineer or an RF engineer.

With the MDO4000, engineers can replace both a scope and spectrum analyzer with a single instrument. This enables them to continue using their tool of choice, the oscilloscope, to look at the frequency domain rather than having to find and relearn a spectrum analyzer.   

Tektronix says the MDO4000 goes beyond typical spectrum analyzer functionality by allowing users to capture time-correlated analog, digital and RF signals across 4 analog, 16 digital and 1 RF channel.  

The RF input frequency range extends up to 6 GHz and provides a capture bandwidth of ≥ 1 GHz at all center frequencies, 100 times wider than typical spectrum analyzers.  Users can see up to 4 decoded serial and/or parallel buses at one time on the same display.  

The time correlation between domains enable accurate timing measurements to understand delays and latencies between command / control events in a design and changes in the RF spectrum.

The MDO4000 also allows designers to see the RF spectrum of a signal at any point in time within a long acquisition to see how the spectrum changes over time or with device state.  By simply moving the Spectrum Time throughout the time domain acquisition, designers can see the RF spectrum for any point in their acquisition while simultaneously seeing their analog, digital and/or decoded buses at the same point in time.

RF time domain traces are used to show how the amplitude, frequency or phase of the RF input signal changes relative to time. This eases the characterization of frequency hop transitions, settling times, and RF event timing relative to other system components and activities. The RF time domain traces are shown in the same window as the analog, digital and serial/parallel bus decoded waveforms.

In addition to the standard RF power level trigger, an optional module (MDO4TRIG) allows additional trigger types to use the RF power level as a source, enabling customers to further isolate an RF event of interest.  Users can trigger on a specific pulse width, or look for a timeout event or runt, or even include the RF input in a logic pattern defined along with the analog and digital channels.  

For system-level debug of wireless-enabled designs the MDO4000 will enable debugging integration of common wireless modules below 6 GHz (WLAN, Bluetooth, Zigbee, etc.), debugging of common ‘home grown’ amplitude, frequency, or phase modulated wireless communications and wideband analysis of dual band transceivers.  For example, capturing both Zigbee at 900 MHz and Bluetooth at 2.4 GHz in a single acquisition.

The timing analysis for mixed domain designs will provide the observation of spectrum changes over time during turn on of VCO/PLLs, measurement of time to stability when turning on or off RF signals and the determination of latencies from control logic signals or serial bus commands to resultant RF changes.

Tracking down sources of noise or interference will be helped by analyzing root cause of radiated or coupled emissions, measuring switch-mode power supply effects on the rest of the system and correlation with time domain signals enables root cause analysis of spurious noise sources.

Stressing the importance of the development, Roy Siegel, general manager, oscilloscopes at Tektronix, said  “It fundamentally changes what’s involved in debugging designs with RF where there is a need to correlate events in the frequency domain with the time domain phenomena that caused them. Just as the mixed signal oscilloscope (MSO) is the standard for embedded design test, we expect the MDO will become the new standard for designs that increasingly include RF capabilities.”

The MDO4000 Series oscilloscopes became available in late August, 2011. Pricing starts at $19,900 U.S. MSRP.

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