Wavecrest DTS-2077 Timing Analyzers

High Performance Timing Analyzer
TheDTS-207x Series Digital Time Scope (DTS) is designed for applicationswhere timing accuracy is critical. The DTS provides direct, real-timemeasurements without the associated errors during the sampling andtransformation of data while waiting for a waveform to be displayed. Theresult is a precision instrument capable of measuring time between twoevents with a resolution of 800 femtoseconds and single-shot measurementaccuracy of ±25 picoseconds (ps).

The DTS represents a dramatic departure from the traditional digitalsampling oscilloscope (DSO) approach to critical timing functions. TheDSO approach takes a time frame and then measures the number of eventsoccurring within that time frame to arrive at a figure for elapsed timebetween each event. The DTS approaches the measurement algorithm asabsolute; time between any twoevents is actual, measurable andquantifiable.

The DTS is intended for AC characterization, with the added benefit ofN.I.S.T. traceability, in applications ranging from ATE test head deskewto bench top device test and computer clock distribution. In addition,the DTS is well suited for scientific and engineering applications whichrequire timing accuracy and resolution more precise then otheravailable instruments can provide.

The DTS achieves greater accuracy with fewer readings in less time thandigital scopes or other types of time domain measurement devices.Long-term measurement accuracy and linearity of the DTS is due tobuilt-in calibration options that can be initiated by the user at anytime.

The DTS incorporates a three-card timing measurement subsystem, asingle-card Central Processing Unit, a comparator card, a front panelfor operator control of the instrument, ovenized crystal oscillator,power supplies, and an IEEE-488 interface. Signals to the DTS areinputted through SMA connectors on the front panel. The front panel(Figure 1-3) provides the means for controlling, monitoring, andcommunicating with all time measurement functions of the DTS.

The DTS-2077 uses a comparator-based front end to make a single-shottime measurement. For details of DTS systems, refer to reference [2].Low Frequency Modulation is a special function of the VISI6 software. Itmeasures a burst of n input events and the associated time jitter. Thisgives one jitter measurement sample. To get a series of jittermeasurement samples, this measurement is continued for a burst ofsamples. Then an FFT is applied to the time jitter series generating ajitter spectrum in the frequency-domain.

The FFT spectrum noise floor is affected by the spectral resolution ofthe Time Digitizer function. In other words, the smaller the spectralresolution, the lower the jitter noise floor and vice versa. For a givenmaximum frequency, the larger the burst sample, the smaller thespectral resolution. In VISI6 this value is input into the Minimum DataPoints box. The largest burst sample that this software tool can make is16384. However, increasing this number will increase the measurementtime.