BK PRECISION 253X Instruction 电路图.pdf
Digital Storage Oscilloscopes Model 2530 25 MHz, 250 MSa/s Model 2532 40 MHz, 500 MSa/s INSTRUCTION MANUAL Models 2530 Normal mode is best for most Pulse Width trigger applications Coupling DC AC HF Reject LF Reject 20 Falling edge Rising edge Triggerlevel can be adjusted vertically Figure 2-7 2.4 Acquisition system When you acquire a signal, the oscilloscope digitizes the signal and displays the resulting waveform on the screen. The acquisition mode defines how the signal is digitized, and the time base setting affects the time span and level of detail in the acquisition. The sampling rate adjusts automatically to a value suitable for each selected Time/Div scaling factor. Refer to Appendix C for more detailed information. Push the ACQUIRE button to access the Acquisition menu Acquire button Figure 2-8 Note: Press the SINGLE button when you want the oscilloscope to acquire a single waveform Trigger coupling affects only the signal passed to the trigger system. It does not affect the bandwidth or coupling of the signal displayed on the screen. Normal Polarity Sync triggers always occur on negative-going horizontal sync pulses. If the video waveform has positive-going horizontal sync pulses, use the Inverted Polarity selection. 21 Table 2- 6 Acquire Menu: The 3 acquisition modes Sample, Peak Detect and Average: ? Sampling： In this acquisition mode, the oscilloscope samples the signal in evenly spaced intervals to reconstruct the waveform. This mode accurately represents the signal most of the time. Advantage: You can use this mode to reduce random noise. Disadvantage: This mode does not capture rapid variations in the signal that may occur between samples. This can result in aliasing and may cause narrow pulses to be missed. In these cases, you should use the Peak Detect mode to acquire data. Figure 2-9 Sampling mode ? Peak Detect： Peak Detect finds the maximum and minimum values of a signal. Advantage: In this way, the oscilloscope can acquire and display narrow pulses, which may have otherwise been missed in Sample mode. Disadvantage: Noise will appear to be higher in this mode. Menu Set up Explanation Sampling Use to acquire and accurately display most waveforms Peak Detect Use to detect glitches and decrease the possibility of aliasing. Average Select this mode to reduce the displayed random noise. Averages 4 16 32 64 128 256 Specify number of averages Mode Equ time Real time Select realtime or equivalent sampling 22 Figure 2-10 Peak Detect mode ? Average: The oscilloscope acquires several waveforms, averages them, and displays the resulting waveform. Advantage: You can use this mode to reduce random noise. Figure 2-11 Average mode ? Equivalent Time Sampling： The equivalent time sampling mode can achieve up to 20 ps of horizontal resolution (equivalent to 50 GSa/s). This mode is good for observing repetitive waveforms. ? Real Time Sampling： The maximum sampling rate for the 2530 is 250 MSa/s and 500MSa/s for the 2532. ? RUN/STOP Button： Press the RUN/STOP button when you want the oscilloscope to acquire waveforms continuously (Run/Stop button is green). Press the button again to stop the acquisition.( Run/Stop button is red) 23 ? SINGLE Button：Push the SINGLE button when you want the oscilloscope to acquire a single waveform and then stop. (Make sure the Run Stop button is green and the display annunciator is in the Ready state). After the oscilloscope detects a trigger, it completes the acquisition then stops. Each time you push the SINGLE button, the oscilloscope begins to acquire another waveform. ? Base time: The oscilloscope digitizes waveforms by acquiring the value of an input signal at discrete points. The time base allows you to control how often the values are digitized. Appendix C details the corresponding sampling rate for each time base setting. To adjust the time base to a horizontal scale that suits your purpose, use the Time/DIV knob. ? Time Domain Aliasing：Aliasing occurs when the oscilloscope does not sample the signal fast enough to construct an accurate waveform record. When this happens, the oscilloscope displays a waveform with a frequency lower than the actual input waveform, or triggers and displays an unstable waveform. Sampled points Apparent low-frequency waveform due to aliasing Actual high-frequency waveform Figure 2-12 2.5 Display System Push the display button to choose how waveforms are presented and to change the appearance of the entire display. Display System Figure 2-13 24 Table 2-7 Figure 2-14 Figure 2-15 Options Set up Explanation Type Vectors Dots Vectors fills the space between adjacent sample points in the display Display sample points Persist Off 1 sec 2 sec 5 sec Infinite Sets the length of time each sampling point remains visible. Contrast Increase the display contrast Decrease the display contrast Format YT XY YT format displays the vertical voltage in relation to time (horizontal scale) XY format displays a dot each time a sample is acquired on channel 1 and channel 2 Screen Normal Inverted set to normal mode set to invert color display mode Grid Display grids and axes on the screen Turn off the grids Turn off the grids and axes 25 2.5.1 X-Y Format Use the XY format to analyze phase differences, such as those represented by Lissajous patterns. The format plots the voltage on channel 1 against the voltage on channel 2, where channel 1 is the horizontal axis and channel 2 is the vertical axis. The oscilloscope uses the untriggered sample acquisition mode and displays data as dots. In this mode, the sampling default sampling rate is 1 MSa/s and is adjustable from 5kSA/s 200 MSa/s. In this mode, the controls operate as followed: The Channel 1“Volts/div”and vertical “POSITION” controls set the horizontal scale and position. The Channel 2“Volts/div”and vertical “POSITION” controls continue to set vertical scale and position. The following functions do not work in XY mode: Reference or math waveform Cursors Autoset（resets display format to YT） Trigger Controls Horizontal Position Knob Vector Display Type Scan Display 2.6 Measurement system There are several ways to take measurements. You can use the graticule, the cursors, or make an automated measurement. Note：The oscilloscope can capture a waveform in normal YT mode at any sampling rate. You can view the same waveform in XY mode. To do so, stop the acquisition and change the display format to XY. Note： When the display Type is set to Vectors, the oscilloscope connects the sample points by using digital interpolation. Interpolation mode contain linearity interpolation and sin(x)/x interpolation. Sin(x)/x interpolation is suitable for real time mode and is most effective at 250ns/div or faster time. The oscilloscope automatically switches to the most suitable display type based on the timebase setting. 26 2.6.1 Graticule Measurement This method allows you to make a quick, visual estimate. For example, you might look at a waveform amplitude and determine that it is a little more than 100 mV. You can take simple measurements by counting the major and minor graticule divisions involved and multiplying by the scale factor. For example, if you counted five major vertical graticule divisions between the minimum and maximum values of a waveform and knew you had a scale factor of 100 mV/division, then you could easily calculate your peak-to-peak voltage as follows: 5 divisions x 100 mV/division = 500 mV. 2.6.2 Cursor Measurement This method allows you to take measurements by moving the cursors, which always appear in pairs, and reading their numeric values from the display readouts. Access the Cursor menu by pressing the Cursor button. Cursors Button Figure 2-16 Table 2-7 Functional Menu of the Cursor Menu Setting Comment Type Voltage Time Off Select and display the measurement cursors. The horizontal cursor measures amplitude and the vertical cursor measures time and frequency. Source CH1 CH2 MATH REFA REFB Select the wave form source to be measured by the cursors Cur1 Activate Cursor 1. Use the ADJUST knob to adjust the cursor position Cur2 Activate Cursor 2. Use the ADJUST knob to adjust the cursor position. 27 Figure 2-17 ? Voltage Cursor： Voltage cursors appear as horizontal lines on the display and measure the vertical parameters. ? Time Cursor： Time cursors appear as vertical lines on the display and measure the horizontal parameters. ? Moving Cursors：Use the ADJUST knob to move cursor1 and cursor2. Cursors can be moved when the cursor menu is displayed. 2.6.3 Auto Measurement “MEASURE”: When you take automatic measurements, the oscilloscope does all the calculating for you. Because this method relies on the digital samples of the waveform, this method is more accurate than graticule or cursor measurements. Auto Measurement button Figure 2-18 Press the MEASURE button. There are 11 types of measurements available. You can display up to five measurements at a time. To define each of the 5 measurements, do the following: 28 1. Press one of the five option buttons corresponding to measurement 1 5 . This will open a sub menu. 2. Enter the Source of the measurement and the measurement type 3. Press the bottom option button to turn the measurement on If you want to display all eleven measurements at once, select “All Mea” from the sub menu (step 2) Voltage Measurements：Max, Min, Peak-Peak, Average, Vrms。 Figure 2-19 Time Measurements：Rise time, Fall time, Frequency, Period, positive pulse width, negative pulse width. Figure 2-20 29 2-8 Measurement Types： * The instrument displays 2500 points. The full record length of 4000 points can be retrieved from internal memory with the included EasyScope application Software Select “All measurements”to display all eleven measurements at once. Fig. 2.21 Measure Type Introduction Vmax Vmax examines the entire 2500 point waveform record and displays the maximum value Vmin Vmin examines the entire 2500 point waveform record and displays the minimum value Vpp Vpp calculates the absolute difference between the maximum and minimum peaks of the entire waveform Vavg Count the arithmetic average value in the record Vrms Calculates a RMS measurement of the first complete cycle of the waveform Rise Rise Time measures the time between 10% and 90% of the first rising edge of the waveform. Fall Fall Time measures the time between 90% and 10% of the first falling edge of the waveform. + Width + Width measures the time between the first rising edge and the next falling edge at the waveform 50% level. - Width -Width Measures the time between the first falling edge and the next rising edge at the waveform 50% level. Prd Measure the Period Freq Measure the Frequency 30 2.7 Utility System ”: The Utility System Button。 Utility Setup button Figure 2-22 Table 2- 9 Utility Menu options Press the UTILITY button to see the “Utility menu” Figure 2-23 Figure 2-24 Option Setting Comment System Status Displays information about the hardware and software configuration Sound This option turns the button beep on or off Counter On Off Turn the Trigger frequency counter On/Off* Language English DO self cal Run the Self Calibration routine Do Self Test Screen Test Keyboard Test LED Test Run a screen test Run a keyboard test Run the LED test 31 2.7.1 System status Selecting “System Status” from the Utility Menu to display information about a particular unit Table 2-10 2.7.3 Self Calibration Before executing the Self Calibration routine, disconnect all probes and leads from the input connector. Then press the “Utility” button and select “Do self cal” to show the self Calibration Menu. Figure 2-25 2.7.4 Self Test Table2-12 Press“UTILITY”“Do Self Test” Display Explanation Startup Times Counts the times the unit was turned on/off. Software version Gives the software version Hardware Version Gives the hardware version Product type Lists the model number Serial No. List the units serial number Option Introduction Screen Test Run Screen Test Program Keyboard Test Run Keyboard Test Program LED Test Run LED Test Program 32 (1) Screen Test： Select “Screen Test” to enter the screen mode. Press the SINGLE key to continue，press RUN/STOP to exit. (2) Keyboard Test Select “Keyboard Test” to enter the key test mode. The shapes with two arrows beside them represent the front panel knobs. The squares represent the knob presses for scale knobs. Test all keys and knobs and verify that all the backlit buttons illuminate correctly. Press RUN/STOP 3 times to exit. (3) LED test Select “LED Test” to run the LED test procedure. Continually press the SINGLE key to step through all the buttons. Press RUN/STOP to exit. 2.8 Save/Recall System Use this menu to save and recall waveforms and setups. The instrument can store/recall 10 setups and 10 waveforms. Save/Recall control button Figure 2-26 SAVE/RECALL SETUP ? SAVE/RECALL Setup： The complete setup is stored in nonvolatile memory. When you recall the setup, the oscilloscope will be in the mode from which the setup was saved. The oscilloscope will automatically save the current setup if you wait three seconds after the last change before you power off the oscilloscope. The oscilloscope recalls this setup the next time you apply power. Up to 10 setups can be recalled/stored. 33 Table 2-13 Figure 2-27 ? RECALL FACTORY: You can use this option to recall the factory setup. Select type Factory then press LOAD. Figure 2-28 Menu Setting Explanation Type Setups Menu for the Storage/Recall setting in the oscilloscope Setup NO.1 to NO.10 Select the memory location to/from which you want to save/recall a setup Save Save a setup to the memory location selected Recall Recall a setup from the memory location selected 34 SAVE/RECALL WAVEFORM ? SAVE/RECALL CAPTURED WAVEFORM： The oscilloscope must display any waveform that you want to save. The oscilloscopes can store ten captured waveforms in nonvolatile memory. Table 2-15 Figure 2-29 SAVE/RECALL REFERENCE WAVEFORM：The oscilloscopes can store two reference waveforms in nonvolatile memory. The oscilloscope can display 2 reference waveforms at a time. Reference waveforms are not adjustable, but the oscilloscope does display the horizontal and vertical scales at the bottom of the screen. (more details see Chapter 3) Option Setup Introduction Type waveforms Menu for the Storage/Recall waveforms in the oscillos
