LeCroy_LW400A_and_B_Series_Operators_Manual_Complete 电路图.pdf

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1、OO P P E E R R A A T T O O R R S S MM A A N N U UA A L L L LWW4 40 00 0 / / L LWW4 40 00 0A A/ / L LWW4 40 00 0B B WWa av ve eS St ta at ti io on n A A P PR RI I L L 1 19 99 99 9 RadioFans.CN 收音机爱 好者资料库 LeCroy Corporation ? however, it has a different functionality. The scratch pad is not directly a

2、ssociated with an output channel. It is, as the name implies, a place to experiment with different waveform options before they are committed to an output. Waveforms can be edited in the scratch pad memory without affecting the state of the output of the AWG. NewThis is the starting point for creati

3、on and naming of a totally new waveform. Pushing the softkey labeled new activates a sub menu permitting selection of a new channel 1 wave, a new channel 2 wave or a new scratch pad wave as a new wave. Selecting one of these three options now causes the system to jump to it?s alphanu- meric entry me

4、nu and permits the user to assign a unique name to this new waveform. Note that alphanumeric entries may also be made via an IBM PC/AT compatible keyboard connected to the Auxilliary Control connector on the rear panel of the LW400. Entries from the keyboard are limited to upper case letters and num

5、bers. The back- space key may be used to delete text. Select Wave Reference Selecting the ReferenceOften it is desirable to see a reference wave. For example, it may be desirable to edit a waveform while viewing the original version of the waveform as it is being edited. The reference wave provides

6、this ability. In the accompanying figure, a reference wave (bottom trace) is shown simultaneously as the WaveStation user prepares to Edit the active Waveform file (top trace). Selecting Reference from the SELECT WAVE menu causes the WaveStation to enter a submenu from which it is possible to choose

7、 the reference wave. The choices are the same as for the channel 1 or channel 2 wave. There is an additional selection to Show Reference. Answering ?yes? permits the reference to be viewed. 3-6 Reference Figure 3.3 Viewing the Reference 3-7 Display Figure 3.4 Setting up the display Splitting the Gri

8、dTo have two grids as in the figure, it is necessary to enter the display menu. Push 2nd followed by DISPLAY and under Type select Dual Grid and push MENU RETURN. For further details see the following section on DISPLAY. DisplayThe Display menu is used to setup the type of display, the grid style, a

9、nd the display intensities. Press the red ?2ND? button and then DISPLAY ( the alternate function of the ZOOM button). The DISPLAY menu, shown in the adjacent figure, will appear. 3-8 Display TypeThe four display types available are Single, Dual, Single and X-Y, and X-Y. Press the Type softkey to ena

10、ble selecting the display type using the rotary knob. Pressing the softkey a second time will show all the choices along with individual softkeys for selection. With Single grid, the selected waveform, or the selected waveform and the reference waveform can be displayed within the same grid. The Dua

11、l grid splits the display into two grids. The selected wave- form is displayed within the top grid. The reference waveform, if enabled by Show Reference switch in the REFERENCE menu, is displayed in the lower grid. The Single and X-Y grid combines an X-Y display and a single display grid. The Refere

12、nce waveform is plotted as the Y (ordinate) axis, while the Selected Waveform is plotted along the X (abscissa) axis. This arrangement permits waveform phase relationships to be investigated as shown in the accompanying figure. Similarly, the X-Y grid provides a full screen view of the reference wav

13、eform plotted against the selected waveform. Figure 3.5 X-Y Single Display 3-9 Display Grid StyleFull, Border, or Cross-Hair grids can be selected by pressing the Grid Style softkey. The Full grid includes graticule lines at each major division in the 8 by 10 division display. The Border style elimi

14、nates all the grid lines except for an outer border. The Cross- Hair grid, as the name implies, consists of a set of perpendicular axes marked with major and minor division increments IntensityThe Intensity menu field is used to set the displayed intensity of the waveforms and annotation. When selec

15、ted, it is adjustable over a range of 1% to 100% using the rotary knob or by numeric entry from the keypad. Likewise, the Grid Intensity allows the user to adjust the brightness of the grid lines independently of the wave- form traces. 3-10 Zoom Figure 3.6 The Zoom Trace Menu ZoomPushing the operati

16、on key labeled ZOOM on the left of the rotary control knob activates the menu that permits selection of the displayed time and amplitude scale factors (zoom factor). The ZOOM controls only affect the display of the waveform. The time base and amplitude settings of the waveform are not affected by th

17、ese settings. There are two major selection fields in this submenu. They are Horizontal and Vertical. Each section has two additional selections: the value at the center and the appropriate scaling in time or volts per division. Pushing the appropriate grey menu button causes the rotary control to a

18、ttach to the function selected. The rotary control is now used to change the value of the selected function. Whenever the rotary control is used to change a numerical value, the resolution of the digit being controlled can be changed by using the left and right digit button located above the rotary

19、control. 3-11 Zoom When a selected numerical quantity is lowered or raised until either the low or high limit is reached, an error message is printed on the screen of the AWG. This error message states for example, ?Cannot decrement this digit? meaning that either incrementing or decrementing the se

20、lected digit will exceed the extreme limit for the field. Display AllDisplay All causes the entire waveform to appear on the screen. It has the effect of undoing any expansions that have previously been invoked both in time and in amplitude. This will effect the display only, and not the current wav

21、eform or output. Zoom to CursorZoom to Cursor will cause the region of the waveform between the time cursors to expand and fill the screen between the 10% to 90% horizontal grid line. Zoom PreviousToggles between the current and previous ZOOM setting. 3-12 ExerciseWaveform selection and zoom 1.Conne

22、ct the AWG to an oscilloscope 2.Push Project 3.Push the softkey next to Open 4.Select the project name APPLICAT.PRJ 5.Push Accept 6.Push Menu Return (this step can be skipped) 7.Push Select Wave 8.Push the grey soft key next to Channel 1 Waveform 9.Select PHOTO.wav 10. Push Menu Return (this step ca

23、n be skipped) 11. Push ZOOM 12. Position Horizontal Center at 12 ?s 13. Expand Horizontal Time/Div to 200 ns 14. Toggle Display All and Zoom Previous Figure 3.7 The Result of Exercise 1 Exercise 4-1 LIVE WAVEFORM MANIPULATIONS 4 Cursor Manipulations Live waveform manipulation means selecting some fe

24、ature of a waveform and changing it while the output is also modified. This change does not occur in real time: there is some delay between feature manipulation in the AWG and a change in the state of the output which is proportional to the size of the area affected. The first step in ?live? wavefor

25、m manipulation is to use the time cursors to select a region of interest in the waveform. This may also involve using the Zoom controls discussed previously. By using Zoom to expand the waveform a detailed examination and selection of waveform elements can be accomplished. This will help assure accu

26、rate results of a waveform manipulation of a specific feature. Time CursorsPressing the Operation key labeled TIME CURSOR next to the rotary control knob activates the menu depicted in figure 4.1 and summarized in table 4.1 below. The time cursors consist of two vertical bars that can be positioned

27、on either side of a waveform feature in order to manipulate extract or delete that feature when Figure 4.1 Time Cursor Menu 4-2 Time Cursor editing. (See editing waveforms in section 6). The time cursors may not cross one another. Time cursors are used in all editing, functions and measurements. Mea

28、surements and Cut editing operations use both cursors while Paste and other Insert opera- tions use the left Cursor. Help ! Where are the Cursors?When the cursors are first turned on, it is possible that they are not visible on screen. Try pushing the softkey labeled Cursors to Grid immediately. The

29、 reason the cursors may not be seen initially is they are located on a portion of the waveform that is outside the field of view. This can occur if, for example, the waveform has been previously expanded and recentered using the ZOOM controls. Notice it is possible to manipulate the cursors indepen-

30、 dent of viewing them: the AWG knows where the cursors are even if they are not being displayed. Similarly Cursors To End may move the cursors off the screen and outside the field of view if the present state of the expansion is such that the end of the wave- form is outside the field of view. Anoth

31、er reason the cursors may not be visible is because they are located directly over a display gradicule line. Turning the rotary control knob will bring the selected cursor into view. Table 4.1 Summary of Time Cursor Operations Time Cursor On/OffThis toggle switch selection turns the timer cursors on

32、 or off Track On/OffWith track set to On, the right cursor moves with left cursor at a fixed time difference (DELTA) when the left cursor is selected and moved. Measure On/OffThis toggle switch turns the measurements on or off Time LeftSelect this field to move the Time Left Cursor Time RightSelect

33、this field to move the Time Right Cursor DeltaChange the delta between the cursors Select All Position the cursors to surround the entire waveform Cursors To GridMove the cursors onto the grid (see discussion below) Cursors To End Move both cursors to the right end of the waveform 4-3 MeasureWhen th

34、e measurements are on they will be displayed in the bottom center of the screen (below the grid). Six measurements will be made: min, max, rise time, fall time, period (PER) and width (WIDP). Min will be the minimum amplitude between the Time Left and Time Right cursors. Max will be the maximum ampl

35、itude between the Time Left and Time Right cursors. Rise time and Fall time will be the first respective qualifying edge after the Time Left cursor and are 10% to 90%. Period will be the time between two odd numbered 50% crossings beginning with the 1st crossings after the left cursor. WIDP is the t

36、ime between adjacent 50% crossings for the first positive pulse between the cursors. See Appendix A for more detail. Voltage CursorsPressing the menu selection key labeled Voltage Cursors next to the rotary control knob activates the submenu seen in figure 4.2 and summarized in the table below. The

37、voltage cursors consist of two horizontal bars that can be positioned up or down along the waveform. The voltage cursors may not cross one another. These cursors are used for making measurements on waveforms. Voltage Cursor Fig. 4.2 Voltage Cursor Menu voltage cursors 4-4 ?Live? ManipulationsMany Ti

38、me Editing operations are performed as quickly as possible in response to user input. The LW400 attempts to compute the desired waveform immediately when the state is changed. If the requested state is changed again before the computation is completed, the partially completed computation is discarde

39、d and a new attempt to compute the desired waveform is begun. If the waveform being edited is the active waveform for one of the channels, then it is automatically updated when the new waveform is computed. The output holds a data point from the previous waveform while the new playback image is bein

40、g loaded. The play- back of the new image begins at its first value. Voltage Cursor Table 4.2 Summary of Voltage Cursor Operations Volt Cursor On/OffThis toggle turns the voltage cursors on or off Track On/OffWith Track set to On, the voltage cursors move together at a fixed voltage difference (DELT

41、A) when the top cursor is moved. Volt TopSelect this field to move the top voltage cursor Volt BottomSelect this field to move the bottom voltage cursor DeltaWith track On, this is the voltage difference between the top and bottom cursors Cursors To GridPosition the cursors on the grid from their cu

42、rrent location 4-5 Time EditPress the Time button in the Edit group to get the menu of figure 4.3. From this menu the duration of part or all of a waveform can be rescaled, or shifted (delayed) in time. Changing the duration of a region always expands or compresses it horizontally: vertical scaling

43、is not affected. DurationStretches and compresses the waveform between the cursors hori- zontally, in time. The left cursor remains in a fixed position and the right cursor moves to the left or right depending on the direction in which the rotary knob is turned. A number for duration can also be ent

44、ered using the numeric keypad. As the right cursor slides in response to the input, the amplitude value at the right cursor remains fixed. The method of insertion depends on the selection of mode described below. Note that using duration provides a quick way to rescale an entire waveform. Using the

45、time cursors, select all, then change duration. Time Edit Fig 4.3 The Edit Time Menu 4-6 Time Edit ModeIn Overwrite Mode the length of the waveform doesn?t change as a region is rescaled: as the region expands, data to the right of the region is overwritten; as the region shrinks, amplitude of the r

46、ight- most point is replicated to keep the waveform length constant. In Insert Mode the waveform size increases and decreases as the region increases and decreases. Move FeatureSlides the region, or feature, between the cursors over the wave- form. As the region slides, the waveform values are linea

47、rly superimposed on each other. The precision with which a feature can be placed is 100 psec. Capture FeatureAs a waveform feature is moved the linear addition causes new ?features? to be formed. That is for example, a pulse sliding over another pulse and adding to it will cause a new pulse that is

48、the sum of the two. If it is now desired to capture this ?new feature? and move it, then press Capture Feature. The memory will now lose the old ?feature? and begin to slide the new ?feature? in it?s place. DelayTakes the entire waveform starting with the left cursor and slides it to the right or le

49、ft by an amount equal to the value in the Delay field. This is done with a maximum precision, or resolution of 100 psec. 4-7 Time Edit Fig. 4.4 Moving the feature in PHOTO.WAV 1.Refer back to Exercise 1 for Waveform Selection since the AWG is going twice as fast as the scope, the new points will be spaced closer together. The choice to preserve the number of points has the potential to change the frequency content of a signal unless the WaveStation clock is adjusted accordingly but it preserves the exact shape of the waveform. Figure 5.2 Insert From Scope 5-4 Insert