LeCroy_2001_Catalog 电路图.pdf

Table of Contents 1 1 Digital Oscilloscopes5 Fundamentals of Digital Oscilloscopes and Waveform Digitizing6 The Benefits of Digital Oscilloscopes15 WavePro Color Oscilloscopes18 WavePro Selection Guide18 WavePro Specifications28 Waverunner-2 Series Color Oscilloscopes34 Waverunner-2 Selection Guide42 Waverunner-2 Upgrade Guide43 Waverunner-2 Specifications45 Waverunner Series Color Oscilloscopes50 Waverunner Series Selection Guide52 Waverunner Upgrade Guide53 LT364,LT364L,LT344,LT344L, LT342,LT342L ,LT322,LT22454 Literunner Digital Oscilloscopes58 Applying the Power of DSOs to High-speed Digital Design60 2 Digitizing Systems69 PXI Digitizers70 High Throughput Digitizers:The LSA1000 Series73 3 Analog Oscilloscopes79 Analog Oscilloscope Selection Guide81 LA35482 LA314/LA314H85 LA302/LA30388 The Analog Advantage91 4 Probes and Accessories97 Passive Probes PP002/PP005/PP006/PP062/PP063/PP06599 Active Probes AP020/AP022103 Active Differential Probes AP033/AP034106 LeCroy Test and Measurement Products Table of Contents RadioFans.CN 收音机爱 好者资料库 2 TABLEOFCONTENTS LeCroy Test and Measurement Products Table of Contents (continued) High Voltage Differential Probes ADP300/ADP305108 Differential Probes AP031110 Differential Amplifiers DA1820A/DA1822A111 DA1850A/DA1855A113 DA1820A-PR2/DA1822A-PR2/DA1850A-PR2/DA1855A-PR2115 Differential Probe Pairs DXC100A116 DXC200117 DXC5100/DA101118 High Voltage Passive Probes PPE1.2kV/PPE2000/PPE4000/PPE20kV 119 Current Probes CP015/CP150120 AP011122 AP015123 General-Purpose Accessories125 Instrument Carts126 Carrying Cases127 5 Jitter and Timing Analysis131 Jitter and Timing Analysis132 Three Views of Jitter133 LeCroy Jitter (Models 374 and 264) L4 Mpt/ch;(Model 374 only) LT3644500 MHz500 MS/s -1GS/s 250 k/500k8.4 TFT LT364L4500 MHz500 MS/s -1GS/s1 M/2 M8.4 TFT LT3444500 MHz500 MS/s 250 k8.4 TFT LT344L4500 MHz500 MS/s1 M8.4 TFT LT3422500 MHz500 MS/s250 k8.4 TFT LT342L2500 MHz500 MS/s1 M8.4 TFT LT3222500 MHz200 MS/s100 k8.4 TFT LT2244200 MHz200 MS/s100 k8.4 TFT LP1422100 MHz500 MS/s 100 k5.7 LCD CONTENTS Digital Oscilloscopes 5 1 CONTENTS Digital oscilloscopes and waveform digitizers sample signals using a fast analog-to-digital converter (ADC).At evenly spaced intervals,the ADC measures the voltage level and stores the digitized value in high-speed dedicated memory. The shorter the intervals,the faster the digitizing rate,and the higher the signal frequency that can be recorded.The greater the resolution of the ADC,the better the sensitivity to small voltage changes.The more memory,the longer the recording time. What are the benefits of this digital technology? Multiple signals associated with intermittent and infrequent events can be captured and analyzed instantly. Complex problems can be quickly identified by viewing waveform data that precedes a failure condition (pre-trigger data).Captured waveforms can be expanded to reveal minute details such as fast glitches,overshoot on pulses,and noise.These captured waveforms can be analyzed in either the time or frequency domains. Some oscilloscopes will: Monitor parameters such as amplitude fluctuations,timing jitter, risetime,etc.,and display worst-case values. Provide histograms of parameter measurements to accurately identify important signal characteristics. Let you use the full screen as a signal- viewing area. Allow signals to be saved or recalled from PC card devices such as portable hard drives,ATA Flash Cards, or IC memory cards. The Instrument Solution When you purchase an instrument,you need to understand basic digitizer speci- fications and architectures to make sure youve selected the right digitizer for the application.For analog oscilloscopes,the primary specifications are simply bandwidth,voltage sensitivity,and accuracy.For digital oscilloscopes,the basic specifications also include sample rate,waveform memory length,vertical resolution,and diagnostic capabilities for troubleshooting.Some architectures are optimized for transient signal capture, while others only record repetitive signals.A general-purpose instrument can capture both single-shot and repet- itive waveforms. Know Your Waveform Before you evaluate digitizers,evaluate your signals.Answering the following questions regarding your signal and the types of measurements needed will help you choose the right instrument.In the long run,this preparation will save time and money. 1. What is the signal bandwidth? 2. How small are the details you need to resolve relative to the peak-to- peak voltage? 3. How accurately do you want to measure voltages and times on the waveforms? 4. How long a waveform portion do you want to capture? 5. What conditions do you need to trigger on? 6. How often should the display update with new waveforms and analyzed results? 7. What kinds of diagnostic tools do you want? 6 FUNDAMENTALS CONTENTS Fundamentals of Digital Oscilloscopes and Waveform Digitizing This technical note discusses how electronic signals are measured by data acquisition instruments and stored as numbers in fast memory. Concepts discussed include data sampling,triggering, recording pre-trigger data, how sampling rate affects usable bandwidth,and how long memory improves sampling rate.There is also a brief discussion of diagnostic capabilities,including standard parameters, frequency analysis (FFT),and statistical analysis (histograms). 1 Digital Oscilloscopes 7 CONTENTS Transient Capture Most analog scopes have a difficult time displaying transient events.In contrast, many digital oscilloscopes are designed for transient capture.Three basic digitizer architectures exist.Transient digitizers and Random Interleaved Sampling (RIS) digitizers can capture transient signals;sampling digitizers cannot.All three types can record repet- itive signals.Only transient and RIS digitizers record pre-trigger waveform information;sampling digitizers cannot. Transient digitizers contain an ADC and waveform memory.Once “armed” ,the ADC digitizes the signal continuously and feeds the samples into memory using circular addressing.After the last memory location is filled,the system overwrites the stored data,starting at the beginning of memory.After a trigger is generated,memory continues to fill with a user-selected number of post-trigger samples.Then the ADC stops feeding the memory.If the user had selected 100% pre-trigger data,the ADC would stop sending data as soon as the trigger arrived.If the user selected 100% post-trigger,the system would fill every memory location one more time and stop.Memory would contain the waveform data that occurred after the trigger. RIS digitizers consist of a transient digitizer with the addition of an interleaved mode.For each trigger,the RIS digitizer records a set of waveform sample points. The digitizer interleaves sample point sets from additional triggered acquisi- tions to construct a detailed representation of the original waveshape. Because the digitizer has no way to know when the trigger will arrive,the sample clock and trigger point are asynchronous.Therefore,the time between the trigger and the very next sample clock randomly varies from waveform acquisition to acquisition.The RIS architecture uses a time-to-digital converter (TDC) to measure this relationship and accurately interleave successive waveform acquisitions.The TDC has much better timing resolution than the sample interval,so RIS recon- structions can reveal details that the transient digitizer alone misses.Yet the RIS digitizer provides user-selectable pre-trigger recording,just like the transient digitizer. Sampling digitizers effectively consist of a sampling head,an ADC,waveform memory,and some timing circuitry.The sampling head stores the voltage and then holds it while the ADC digitizes it. Sampling digitizers acquire just one sample per trigger.For each successive trigger,the timing circuitry delays the time from the trigger to the sample point.For example,for an equivalent sample rate of 1 GS/s,the first sample point would be at the trigger point,the second delayed by 1 ns, the third delayed by 2 ns,and so on.Because the sample points are delayed from the trigger point,sampling digitizers cannot record pre-trigger information. ClockClock MemoryMemory A D A D T D T D G TriggerTriggerG 1 ns glitch digitized at 500 MS/s.It is impossible to accurately determine amplitude or width. The same glitch sampled at 10 GS/s.Both pulse width and peak amplitude can be accurately measured. RIS digitizer block diagram. 8 With one sample per trigger,sampling digitizers can take a long time to construct long waveform records.For example, for a 1,000-point long record, they require 1,000 waveforms to occur, and for a 50,000-point record,50,000 waveforms. Bandwidth and Sample Rate Bandwidth is an important specification for digitizers,just like for analog scopes. The digitizers filters and input amplifiers determine the bandwidth.Fast pulse edges and sharp waveform peaks contain high-frequency signal compo- nents.To accurately record these edges and peaks,the digitizer must have adequate bandwidth to pass these high- frequency signal components with minimal attenuation. How much bandwidth is enough? To accurately indicate signal peak ampli- tudes,the digitizer bandwidth should exceed the signal bandwidth.First determine the signal bandwidth by estimating the fastest pulse risetime in your signal.Assuming a single pole system response,the signal bandwidth is as follows: Signal Bandwidth 0.35/(10% - 90% risetime) For example,a signal with 1 ns risetime (1 x 10-9s) has a bandwidth of 350 MHz (350 x 106per second). Note that real world instruments which measure signal risetimes are rarely a simple single pole system.The factor of 0.35 used in the equation above could range as high as 0.5. The bandwidth of a signal digitizer system is determined by measuring the pass band.Typically,a sinewave with fixed amplitude is used as an input and the frequency is increased to the point at which the signal is attenuated by 3 dB (29%).This attenuation occurs gradually, starting at a much lower frequency. Therefore,choose a digitizer with higher bandwidth than the signal. Sample Rate Effects on Usable Bandwidth The digitizer sample rate can degrade the usable bandwidth.To ensure adequate sampling,obtain at least four samples per cycle of the fastest signal in the waveform.For precision measure- ments,10 samples per cycle may be desirable.In all cases,more samples will result in a better measurement.If your signal is transient,then look at the single- shot sample rate specification;if repetitive,the faster equivalent-time sample rate can be used. LeCroy WavePro oscilloscopes can sample at rates up to 16 GS/s in real time or 50 GS/s in a repetitive (RIS)mode. Given this ideal the digitizer with no noise and a bandwidth-limited signal Nyquist criterion holds true.Nyquist states that at least two samples must be taken for each cycle of the highest measurable input frequency.In other FUNDAMENTALS CONTENTS S H S H Trigger Generator Memory A D A D Sampling digitizer block diagram. Sampling digitizer operation. Attenuation occurs within the passband,not just at the cutoff (-3 dB) frequency. Input Frequency (Relative to -3 dB Frequency (F0) Attenuation dB% 1.0 Fo-3 dB29% 0.5 Fo-1 dB-11% 0.1 Fo0.1 dB-1% 1 Digital Oscilloscopes 9 words,the highest input frequency cannot exceed one half the sample rate. Given this scenario,a sin(x)/x interpo- lation algorithm can reproduce the digitized input signal fairly accurately. The sin(x)/x algorithm fits curve segments between sample points to create a smooth waveform represen- tation.Unfortunately,sin(x)/x interpolation can amplify noise.Because noise exists in real signals and digitizers, sin(x)/x should be used cautiously, especially with less than four samples per cycle. Sin(x)/x algorithms also can create undesirable overshoot and preshoot on fast edges.At least two data samples are required on the fastest signal edge.It is important that the user be able to examine the number of raw data points acquired in any scope using sin(x)/x display. Maintaining Usable Bandwidth Long memory allows the scope to maintain the fastest specified sample rate on more timebase settings than a shorter-memory scope.Memory deter- mines the maximum possible sample rate at a particular timebase setting,as follows: Sample = Waveform Memory Rate (Timebase Setting) * (# CRT Horiz.Divisions) For example,if the digitizer contained 50,000 points of memory and 10 CRT display divisions and the timebase was set to 5 s/div,the sample rate could be as high as 1 GS/s and still fill the screen. As the timebase is lengthened (more time per division),the digitizer must reduce its sample rate to record enough signal to fill the display screen.By reducing the sample rate,it also degrades the usable bandwidth.Long- memory digitizers maintain their usable bandwidth at more timebase settings than short-memory digitizers.This allows the user to see more detail in the signal and to make more accurate measurements. Benefits of Long Memories in Digital Oscilloscopes Increasing the DSO memory length brings many advantages,not all of them obvious.Among these are: No missed details on waveforms, thanks to higher effective sampling rate. Permanent glitch capture,without waveform distortion. Better time and frequency resolution. Reliable capture of events that are unpredictable in time. No dead time between acquired events by using long memory to seamlessly acquire those events. The ability to segment long memory into a sequence of separately triggered events with minimal deadtime (typically 25-30 sec). No Missed Details Figures 1 and 2 show the same waveform (a 20 ms video signal) acquired by two different scopes configured with memory lengths of one million and one hundred thousand points,respectively.The superior resolution of the longer-memory scope is best seen by comparing the expanded portion of its waveform in Figure 1 (lower trace) with the expansion in Figure 2 from the shorter- memory scope.The longer-memory scope shows the waveform undistorted by the undersampling evident in the shorter-memory scope. This example illustrates the effect of record length upon sampling rate.Both scopes are displaying 20 ms of data (10 divisions at 2 ms/div).Thus,the 100 kpoint scope is digitizing at: CONTENTS Figure 1:Capturing a frame of video using 1 million points of acquisition memory allows 20 ms of data to be sampled at 50 MS/s. Figure 2:The same signal captured by a 100 k memory scope.The trace is undersampled as shown in the expansion below the main trace.The same 20 ms of data causes the sampling rate to become 5 MS/s due to shorter memory. 10 20 ms/100,000= 0.2 s per point = 5 MS/s while the 1 Mpoint scope is digitizing at: 20 ms/1,000,000= 20 ns per point = 50 MS/s Hence,the sample rate is a direct function of memory length.(This is true up to the limit of the scopes maximum sample rate.) As a resul