lecroy 93XXC-OM-E10 电路图.pdf

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1、? ? 7ULJJHUV?DQG?:KHQ?WR?8VH?7KHP low when less than this threshold (Fig. 815). For example, the pattern could be defined as present when the trigger state for CH 1 is high, CH 2 is low, and EXT is irrelevant (X or dont care). If any of these conditions are not met, the pattern state is considered a

2、bsent. Limits can be selected from 10 ns to 20 s. Figure 814. Pattern Trigger Menu (see page 833). NOT AVAILABLE ON 9304C, 9310C, 9314C SERIES Pattern Trigger on Pattern with CouplingDC|AC|LFREJ|HFREJ 1|2|3|4|Ext (according to model) Exiting|Entering LevelL|H|X|(Level value) Off| Time (10 ns to 20 s

3、) |Evs (1 to 99 999 999) Holdoff ? $SSOLFDWLRQVPattern Trigger is useful in digital design for the testing of complex logic inputs or data transmission buses. Figure 815. Pattern Trigger: Trigger when pattern conditions met. CH 1 Generated Trigger (Pattern Entering) Pattern 1H*2L Threshold CH 2 Gene

4、rated Trigger (Pattern Exiting) Threshold High High Low Low ? 7ULJJHUV?DQG?:KHQ?WR?8VH?7KHP 0RUH?$ERXW?3DWWHUQ?7ULJJHU Once the pattern is defined, one of two transitions can be used to generate the trigger. When the pattern begins, called entering the pattern, a trigger can be generated. Alternativ

5、ely, a trigger can be generated when the pattern ends, exiting the pattern. With pattern triggering, as in single source, either of these qualifications can be selected: Hold-off for 10 ns up to 20 s, or Hold-off for 1 to 99 999 999 events. Set to Pattern Trigger, the oscilloscope always checks the

6、logic AND of the defined input logic states. However, with the help of de Morgans laws, the pattern becomes far more generalized. Consider the important example of the Bi-level or Window Pattern Trigger. Bi-level implies the expectation of a single-shot signal on which the amplitude will go in eithe

7、r direction outside a known range. To set up a Bi-level Pattern trigger, connect the signal to two inputs: Channels 1 and 2 or any other pair that can be triggered on. For example, the threshold of CH 1 could be set to +100 mV and that of CH 2 at 200 mV. The Bi-level Trigger will occur if the oscill

8、oscope triggers on CH 1 for any pulse greater than +100 mV, or on CH 2 for any pulse less than 200 mV. For improved precision, the gains of the two channels should be at the same setting. In Boolean notation we can write: TriggerCH 1CH 2=+, i.e. trigger when entering the pattern CH 1 = high OR CH 2

9、= low. By de Morgans laws this is equivalent to: TriggerCH 1 CH 2=, i.e. trigger when exiting the pattern CH 1 = low AND CH 2 = high. This configuration can be easily programmed. The possibility of setting the threshold individually for each channel extends this method so that it becomes a more gene

10、ral Window Trigger: in order to trigger the input pulse amplitude must lie within or outside a given arbitrary window. Pattern Trigger has been designed to allow a choice of the trigger point. By choosing 1L*2H entering, the trigger will occur at the moment the pattern 1L*2H becomes true. ? 4XDOLILH

11、G?7ULJJHUVIn the case of Qualified Triggers (Fig. 816), a signals transition above or below a given level, the validation, serves as an enabling, or qualifying, condition for a second signal that is the source of the trigger. Two Qualified Triggers are available: State-Qualified, where the amplitude

12、 of the first signal must remain in the desired state until the trigger occurs, and Edge-Qualified, for which the validation is sufficient and no additional requirement is placed on the first signal. A Qualified Trigger can occur immediately after the validation or within a set time after it. Or it

13、can occur following a predetermined time delay or number of potential trigger events. The time delay or trigger count is restarted with every validation. Figure 816. State- and Edge-Qualified Trigger Menus (see pages 835 and 836). Qualified By Trigger on After1|2|3|4|Ext|Ext10|Pattern 1|2|3|4|Ext|Ex

14、t10 Edge|State qualifier Has goneAbove|Below|Value Off|Time (10 ns to 20 s)| Evs (1 to 99 999 999) Wait Qualified By Trigger on Only after1|2|3|4|Ext|Ext10|Pattern 1|2|3|4|Ext|Ext10 Edge|State qualifier Goes and stays Above|Below|Value Wait Off|Time (10 ns to 20 s)| Evs (1 to 99 999 999) ? 7ULJJHUV?

15、DQG?:KHQ?WR?8VH?7KHP Qualified Triggers offer the choice of generating a trigger either when the selected pattern is present or absent. As with Pattern Trigger, the pattern is defined as a logical AND combination of trigger states that are either high or low: high when a trigger source is greater th

16、an the selected trigger level, and low when it is less than. For example, a pattern might be defined as present when the trigger states for Channels 1 and 2 are high and EXT is low. If any of these conditions is not met, the pattern state is considered absent. Qualified Triggers allow an additional

17、qualification once the selected pattern state occurs. For example: “wait for 10 ns up to 20 s, trigger on CH 1 to the 99 999 999th event”. The pattern is used to qualify the trigger without actually generating it. Triggering will occur when another signal, the trigger source, meets its trigger condi

18、tion while the pattern is present. The trigger source itself is not allowed in the pattern. $SSOLFDWLRQVTypical applications can be found wherever time violations occur, such as in micro-processor debugging or telecommunications. 6WDWH?4XDOLILHG?ZLWK?:DLWState-Qualified Trigger with Wait (Fig. 817)

19、is determined by the parameters of Time and number of Events: ? Time selects a delay from the start of the desired pattern. After the delay (timeout) and while the pattern is present, a trigger can occur. The timing for the delay is restarted when the selected pattern begins ? Events selects a minim

20、um number of events of the trigger source. An event is generated when a trigger source meets its trigger conditions. On the selected event of the trigger source and while the pattern is present, a trigger can occur. The count is initialized and started whenever the selected pattern begins, and conti

21、nues while the pattern remains. When the selected count is reached, the trigger occurs. ? Figure 817. State-Qualified by Wait: Trigger after timeout. As Figure 817 illustrates, a trigger is generated on a rising edge whenever the pattern is asserted (pattern present) and the wait timeout has expired

22、. The timeout is, respectively, activated or disabled once the pattern is asserted or absent. Generated Trigger Selected wait Trigger Source: Positive Slope Trigger can occur Qualifier: Pattern Present ? 7ULJJHUV?DQG?:KHQ?WR?8VH?7KHP (GJH?4XDOLILHG?ZLWK?:DLWLike its State-Qualified equivalent, Edge-

23、Qualified with Wait (Fig. 818) is conditioned by Time and Events: ? Time Selects a delay from the start of the desired pattern. After the delay (timeout) and before the end of the pattern, a trigger can occur. The timing for the delay is restarted when the selected pattern begins. ? Events selects a

24、 minimum number of events of the trigger source. An event is generated when a trigger source meets its trigger conditions. On the selected event of the trigger source and before the end of the pattern, a trigger can occur. The count is initialized and started whenever the selected pattern begins. It

25、 continues while the pattern remains. When the selected count is reached, the trigger occurs. Figure 818. Edge-Qualified by Wait: Trigger after timeout. T Selected time T Trigger Source: Positive Slope Qualifier: Pattern Present Trigger can occur Generated Trigger ? 79?7ULJJHUA special kind of Edge-

26、Qualified Trigger, TV Trigger allows stable triggering on standard or user-defined composite video signals, on a specific line of a given field. Applications can be found wherever TV signals are present. And TV Trigger can be used on PAL, SECAM or NTSC systems. A composite video signal on the trigge

27、r input is analyzed to provide a signal for the beginning of the chosen field “any”, “odd” or “even” and for a signal at the beginning of each line. The field signal provides the starting transition, and the beginnings of line pulses are counted to allow the final trigger on the chosen line. Each fi

28、eld, the number of fields, the field rate, interlace factor, and number of lines per picture must be specified although there are standard settings for the most common types of TV signals. TV Trigger can also function in a simple any-line mode. Figure 819. TV Trigger Menus (see page 834 ) TV TV sign

29、al on # of fields TV typeStandard | Custom 1|2|4|8 1|2|3|4|Ext|Ext 10 as: 625/50/2:1| 525/60/2:1 (Standard) as: Line| Hz | Interlacing 1 to 1500| 50/60 | 1:1/2:1/ 4:1/8:1/ (Custom) Trigger onLine | Field ? 7ULJJHUV?DQG?:KHQ?WR?8VH?7KHP 1RWHV?IRU?79?7ULJJHU ? Because most TV systems have more than tw

30、o fields, the enhanced field-counting capability (FIELDLOCK) allows the oscilloscope to trigger consistently on a chosen line within a chosen field of the signal. The field-numbering system is relative, in that the oscilloscope cannot distinguish between lines 1, 3, 5, and 7 (or 2, 4, 6, and 8) in a

31、n absolute way. ? For each of the characteristics the following remarks apply: ? 625/50/2:1 (PAL and SECAM systems) This setting should be used for most of the standard 50-field signals. The lines may be selected in the range 1 to 626 where line 626 is identical to line 1. Number of fields: eight is

32、 most useful for color PAL signals; four for SECAM signals. ? 525/60/2:1 (NTSC systems) This setting should be used for standard 60-field NTSC signals. The lines can be selected in the range 1 to 1051, where line 1051 is identical to line 1. Number of fields: four is most useful for US-type NTSC sys

33、tems. ? ?/50/?, ?/60/? In order to allow maximum flexibility, no line-counting convention is used. The line count should be thought of as a line-synchronizing pulse count. It includes the transitions of the equalizing pulses. For certain extreme cases, the field transition recognition will no longer

34、 work, and only the “any line” mode will be available. ? The enhanced field-counting capability cannot be used for RIS acquisitions. ? Composite video signals must have negative-going synch to be decoded correctly. ? URSRXW?7ULJJHUDropout Trigger (Fig. 820) provides triggering whenever the signal di

35、sappears for a selectable period of time. The trigger is generated at the end of the time-out period following the “last” trigger source transition. Time-outs of between 25 ns and 20 s can be selected. Figure 820. Dropout Trigger Menu (see page 837) $SSOLFDWLRQVDropout Trigger is useful for detectin

36、g interruptions in data streams such as network hang-ups and microprocessor crashes. A typical application is on the last normal interval of a signal that has disappeared completely. This is essentially a single-shot application, usually with a pre-trigger delay. RIS acquisition is not useful here b

37、ecause the timing of the trigger timeout is insufficiently correlated with the input channel signals. Dropout Trigger after timeout if no edge occurs on With slope WithinTime (25 ns to 20 s) Positive|Negative 1|2|3|4|Ext|Ext10 ? 7ULJJHUV?DQG?:KHQ?WR?8VH?7KHP Figure 821. Dropout Trigger: A trigger oc

38、curs when the timeout has expired. Generated Trigger Wait timeout Trigger Source Trigger can occur ? 75,*(5?6(783?60$57 Press to access, too, the various SMART Trigger types, to trigger on: ? Glitches ? Intervals ? Abnormal signals (Exclusion Trigger) ? Patterns (NOT AVAILABLE ON 9304C, 9310C, 9314C

39、 SERIES) ? State- or edge-qualified events ? TV signals ? Dropouts. (GJH?60$57?To select “SMART 6(783?60$57?75,*(5 This is primary menu that accesses the “SMART TRIGGER” menu group, for choosing the type of SMART Trigger required from the “type” secondary menu. This and the other SMART menus are des

40、cribed starting page 830. ? 7ULJJHUV?DQG?:KHQ?WR?8VH?7KHP 60$57?75,*(5?*OLWFK WSH To select “Glitch”. WULJJHU RQ For selecting the trigger source (four-channel menu shown). FRXSOLQJ To select the trigger coupling. DW?HQG?RI To define the test on either “Pos”-itive or “Neg”-ative pulses. ZLGWK? When

41、“On” instructs the instrument to trigger if the pulse is smaller than the value defined in this field. The value can be adjusted with the associated menu knob, while the test can be turned on or off by pressing the menu button, and used in combination with the “width ” test. Width values in the rang

42、e 2.5 ns to 20 s can be entered. ?ZLGWK? “On” instructs the instrument to trigger if the pulse is greater than the value defined in that field. The value can be adjusted using the associated menu knob, and the test turned on or off with the menu button in combination with the “width ” test menu sele

43、ction. The two width limits are combined to select glitches within (“&”) a certain range if the “width ” value is greater than the “width ” value. Otherwise, they are combined to select glitches outside this range. ? 60$57?75,*(5?*OLWFK?3DWWHUQ?(NOT ON 9304C, 9310C, 9314C SERIES) When “Pattern” is s

44、elected in Glitch mode, the instrument triggers on the logic AND of up to five sources. WSH To select “Glitch”. WULJJHU?RQ To select “Pattern” (four-channel menu shown). IRU?SDWWHUQ For selecting pattern “Present” or “Absent”. ZLGWK? To trigger if the pattern is present or absent for less than the t

45、ime value defined in that field. The value can be adjusted with the associated menu knob and the test commuted to “” by pressing the corresponding menu button. ?ZLGWK? To trigger if the pattern is present or absent for more than the time value defined in that field. The value can be adjusted and the

46、 test commuted to “?” as per “width ?”. ? 7ULJJHUV?DQG?:KHQ?WR?8VH?7KHP 60$57?75,*(5?,QWHUYDO WSH To select “Interval”. WULJJHU?RQ For selecting the trigger source (four-channel menu shown). FRXSOLQJ For selecting the trigger coupling. EHWZHHQ To define the interval between two adjacent “Pos”-itive

47、or “Neg” -ative edges. LQWHUYDO? To trigger if the interval is smaller than the value defined here, which can be adjusted using the associated knob. The test can be turned on or off with the corresponding menu button, and can be used in combination with the “interval ” test. Interval values in the r

48、ange 10 ns to 20 s may be entered. 25?LQWHUYDO? To trigger if the interval is greater than the value defined here, which can be adjusted using the associated menu knob The test can be turned on or off using the corresponding menu button, and can be used in combination with the “interval ” test. The

49、two interval limits are combined to select intervals within (“&”) a range if the “interval ” value is greater than the “interval ” value. Otherwise they are combined to select intervals outside (“OR”) the range. ? 60$57?75,*(5?3DWWHUQ?(NOT ON 9304C, 9310C, 9314C SERIES) WSH To select “Pattern”. WULJJHU?RQ To select “Entering” for the scope to trigger when the pattern starts being true, and “Exiting” for triggering when it stops being true. 3DWWHUQ?ZLWK For selecting the channel to be modified using the lower menus correspondin