Q11: What is the difference between external triggering and self-triggering when looking at the waveform on the oscilloscope?
A: The usual trigger of oscilloscope is edge trigger, and its trigger conditions are 2, trigger level and trigger edge; that is: when the rising edge (or falling edge) of the signal reaches a specific level (trigger level), the oscilloscope triggers. The oscilloscope will only use external trigger when there is a problem with the signal self-triggering, there is no question of which is better. And this problem may usually be, the signal is more complex, there are many points to meet the trigger conditions, can not be triggered at the same location each time, so as to get a stable display. This is when you need to use external triggering. For example, if you observe the signal above, the oscilloscope will not display a stable waveform because all the ABCD points will be triggered. At this time, you can use the following signal as the trigger signal, and the oscilloscope will get a display that is capable of all cycles.
Q12: How to understand the bandwidth in the oscilloscope index?
A: Bandwidth is the basic indicator of the oscilloscope, and the definition of the amplifier bandwidth, is the so-called -3dB point, that is, the input of the oscilloscope plus a sine wave, the amplitude decay to 70.7% of the actual amplitude of the frequency point called bandwidth. In other words, using a 100MHz bandwidth oscilloscope to measure 1V, 100MHz sine wave, the amplitude obtained is only 0.707V. and that's just the case of sine wave. Therefore, when choosing an oscilloscope, we should choose a bandwidth of 5 times the maximum frequency of the signal in order to achieve a certain measurement accuracy.
Q13: How to get the total bandwidth of the measurement system?
A: The total bandwidth of the measurement system = 0.35/rise time (for oscilloscopes below 1GHz).
Q14: What are the factors that affect the operating speed of Yokogawa oscilloscopes?
A: In fact, the principle of any oscilloscope is similar, the front end is the data acquisition system, and the back end is the computer processing. There are two main aspects affecting the speed, one is the data transmission from the front-end data acquisition to the back-end processing, generally with PCI bus, this is the transmission bottleneck, but there are new technologies can break through; the other is the back-end processing, improve the processing speed can be achieved through data packet sharing.
Q15: Digital oscilloscope applications of various triggers, such as edge trigger, burr trigger and pulse width trigger, they are each suitable for testing the kind of signal?
A: edge trigger, edge trigger, can set the trigger level, rising edge or falling edge. Edge trigger is also called basic trigger. advanced trigger, that is, advanced trigger, which covers a variety of different trigger functions, according to the characteristics of the signal under test, set the corresponding trigger conditions, locate the waveform of interest. Advanced trigger is the key to circuit debugging. In the process of circuit debugging, if you do not know the possible problems of the signal under test beforehand, you can use Tektronix digital fluorescent oscilloscope to quickly find various problems in the circuit by using 400,000/sec waveform capture speed, and then use different advanced trigger functions to locate the details of the fault, which can shorten your debugging cycle.
Q16: How to eliminate burrs when using the oscilloscope?
A: If the burr is inherent in the signal itself and you want to synchronize the signal with edge trigger (such as sine signal), you can use high frequency suppression trigger method, which can usually synchronize the signal. If the signal itself has a burr, but you want the oscilloscope to filter out the burr and not show the burr, it is usually difficult to do. You can try to use the method of limiting the bandwidth, but accidentally you may also filter out some of the information from the signal itself. If you use a logic analysis instrument, in general, using the state acquisition method, some of the burrs that are acquired in the timing method will not be visible.
Q17: In practice, when encountering sudden burr signals, how to capture and test them?
A: For example, we often encounter occasional burr signal when clock testing, the signal will produce a false movement on our circuit, so capture the signal becomes the key to testing, because we can not determine the burr is positive or negative in advance, so we must first use the TDS5000 oscilloscope digital fluorescence function that is fast waveform capture mode combined with infinite afterglow view burr characteristics, and then use the The advanced trigger function of the oscilloscope - pulse width trigger according to the signal characteristics, such as: less than the normal clock pulse width trigger.
Q18: What are the applications of burr / pulse width trigger?
A: Burr / pulse width trigger generally has two typical applications, one is to synchronize the circuit behavior, such as the use of it to synchronize the serial signal, or for applications with very serious interference, can not be correctly synchronized signal with edge trigger, pulse width trigger is a choice; the other is used to find the anomaly in the signal, such as interference or competition caused by narrow burr, because the anomaly is incidental appear, must be used to burr trigger to capture (another method is the peak detection method, but the peak detection method is likely to be limited by its maximum sampling rate, at the same time, generally can be seen, not measured). If the pulse width of the object under test is 50ns, and the signal does not have any problems, that is, there is no distortion or narrower signal caused by interference, competition and other problems, the signal can be synchronized with edge triggering, no need to use burr triggering. Fortunately, the 5462x and 546?x are among the few instruments in the industry that can do this, as many users set the pulse width trigger to 10ns ~ 30ns. If you want to verify that there are no abnormal pulses in that 10MHz square wave, including pulses that are much narrower than 50ns, you will use pulse width or burr triggering, and possibly the 5ns setting.
Q19: Does it make much sense to have a large sampling frequency with a certain bandwidth?
A: Bandwidth is the basic condition that limits the high frequency component of the measured signal to be captured. With Tektronix oscilloscopes, only 2.5 points per measured signal period is required to maximize waveform reconstruction. Other oscilloscopes require more than 4 sample points/cycle, i.e. 100MHZ bandwidth oscilloscopes require at least 400MS/s sample rate for a single acquisition, and some oscilloscopes even require 10 points (linear interpolation technique) to ensure that the acquired signal is meaningful.
Q20: When choosing an oscilloscope, the general consideration is more bandwidth. So, in what case to consider the sampling rate?
A: Depending on the object under test, the minimum sampling interval (inverse of the sampling rate) is expected to capture the signal details you need, provided the bandwidth is satisfied. Some industry experience on the sampling rate formula, but basically for the oscilloscope bandwidth derived from the actual application, it is best not to use the oscilloscope to measure the same frequency signal. If you are selecting a sine waveform, choose an oscilloscope bandwidth that is 3 times the frequency of the sine signal being measured, or more, the sample rate is 4 to 5 times the bandwidth, which is actually 12 to 15 times the signal, and for other waveforms, make sure the sample rate is sufficient to capture the signal details. If you are using an oscilloscope, you can verify that the sample rate is sufficient by stopping the waveform, zooming in on it, and finding that if the waveform changes (e.g., some amplitude), the sample rate is insufficient, otherwise it is fine. You can also use the dot display to analyze whether the sample rate is sufficient.
Q11: What is the difference between external triggering and self-triggering when looking at the waveform on the oscilloscope?
A: The usual trigger of oscilloscope is edge trigger, and its trigger conditions are 2, trigger level and trigger edge; that is: when the rising edge (or falling edge) of the signal reaches a specific level (trigger level), the oscilloscope triggers. The oscilloscope will only use external trigger when there is a problem with the signal self-triggering, there is no question of which is better. And this problem may usually be, the signal is more complex, there are many points to meet the trigger conditions, can not be triggered at the same location each time, so as to get a stable display. This is when you need to use external triggering. For example, if you observe the signal above, the oscilloscope will not display a stable waveform because all the ABCD points will be triggered. At this time, you can use the following signal as the trigger signal, and the oscilloscope will get a display that is capable of all cycles.
Q12: How to understand the bandwidth in the oscilloscope index?
A: Bandwidth is the basic indicator of the oscilloscope, and the definition of the amplifier bandwidth, is the so-called -3dB point, that is, the input of the oscilloscope plus a sine wave, the amplitude decay to 70.7% of the actual amplitude of the frequency point called bandwidth. In other words, using a 100MHz bandwidth oscilloscope to measure 1V, 100MHz sine wave, the amplitude obtained is only 0.707V. and that's just the case of sine wave. Therefore, when choosing an oscilloscope, we should choose a bandwidth of 5 times the maximum frequency of the signal in order to achieve a certain measurement accuracy.
Q13: How to get the total bandwidth of the measurement system?
A: The total bandwidth of the measurement system = 0.35/rise time (for oscilloscopes below 1GHz).
Q14: What are the factors that affect the operating speed of Yokogawa oscilloscopes?
A: In fact, the principle of any oscilloscope is similar, the front end is the data acquisition system, and the back end is the computer processing. There are two main aspects affecting the speed, one is the data transmission from the front-end data acquisition to the back-end processing, generally with PCI bus, this is the transmission bottleneck, but there are new technologies can break through; the other is the back-end processing, improve the processing speed can be achieved through data packet sharing.
Q15: Digital oscilloscope applications of various triggers, such as edge trigger, burr trigger and pulse width trigger, they are each suitable for testing the kind of signal?
A: edge trigger, edge trigger, can set the trigger level, rising edge or falling edge. Edge trigger is also called basic trigger. advanced trigger, that is, advanced trigger, which covers a variety of different trigger functions, according to the characteristics of the signal under test, set the corresponding trigger conditions, locate the waveform of interest. Advanced trigger is the key to circuit debugging. In the process of circuit debugging, if you do not know the possible problems of the signal under test beforehand, you can use Tektronix digital fluorescent oscilloscope to quickly find various problems in the circuit by using 400,000/sec waveform capture speed, and then use different advanced trigger functions to locate the details of the fault, which can shorten your debugging cycle.
Q16: How to eliminate burrs when using the oscilloscope?
A: If the burr is inherent in the signal itself and you want to synchronize the signal with edge trigger (such as sine signal), you can use high frequency suppression trigger method, which can usually synchronize the signal. If the signal itself has a burr, but you want the oscilloscope to filter out the burr and not show the burr, it is usually difficult to do. You can try to use the method of limiting the bandwidth, but accidentally you may also filter out some of the information from the signal itself. If you use a logic analysis instrument, in general, using the state acquisition method, some of the burrs that are acquired in the timing method will not be visible.
Q17: In practice, when encountering sudden burr signals, how to capture and test them?
A: For example, we often encounter occasional burr signal when clock testing, the signal will produce a false movement on our circuit, so capture the signal becomes the key to testing, because we can not determine the burr is positive or negative in advance, so we must first use the TDS5000 oscilloscope digital fluorescence function that is fast waveform capture mode combined with infinite afterglow view burr characteristics, and then use the The advanced trigger function of the oscilloscope - pulse width trigger according to the signal characteristics, such as: less than the normal clock pulse width trigger.
Q18: What are the applications of burr / pulse width trigger?
A: Burr / pulse width trigger generally has two typical applications, one is to synchronize the circuit behavior, such as the use of it to synchronize the serial signal, or for applications with very serious interference, can not be correctly synchronized signal with edge trigger, pulse width trigger is a choice; the other is used to find the anomaly in the signal, such as interference or competition caused by narrow burr, because the anomaly is incidental appear, must be used to burr trigger to capture (another method is the peak detection method, but the peak detection method is likely to be limited by its maximum sampling rate, at the same time, generally can be seen, not measured). If the pulse width of the object under test is 50ns, and the signal does not have any problems, that is, there is no distortion or narrower signal caused by interference, competition and other problems, the signal can be synchronized with edge triggering, no need to use burr triggering. Fortunately, the 5462x and 546?x are among the few instruments in the industry that can do this, as many users set the pulse width trigger to 10ns ~ 30ns. If you want to verify that there are no abnormal pulses in that 10MHz square wave, including pulses that are much narrower than 50ns, you will use pulse width or burr triggering, and possibly the 5ns setting.
Q19: Does it make much sense to have a large sampling frequency with a certain bandwidth?
A: Bandwidth is the basic condition that limits the high frequency component of the measured signal to be captured. With Tektronix oscilloscopes, only 2.5 points per measured signal period is required to maximize waveform reconstruction. Other oscilloscopes require more than 4 sample points/cycle, i.e. 100MHZ bandwidth oscilloscopes require at least 400MS/s sample rate for a single acquisition, and some oscilloscopes even require 10 points (linear interpolation technique) to ensure that the acquired signal is meaningful.
Q20: When choosing an oscilloscope, the general consideration is more bandwidth. So, in what case to consider the sampling rate?
A: Depending on the object under test, the minimum sampling interval (inverse of the sampling rate) is expected to capture the signal details you need, provided the bandwidth is satisfied. Some industry experience on the sampling rate formula, but basically for the oscilloscope bandwidth derived from the actual application, it is best not to use the oscilloscope to measure the same frequency signal. If you are selecting a sine waveform, choose an oscilloscope bandwidth that is 3 times the frequency of the sine signal being measured, or more, the sample rate is 4 to 5 times the bandwidth, which is actually 12 to 15 times the signal, and for other waveforms, make sure the sample rate is sufficient to capture the signal details. If you are using an oscilloscope, you can verify that the sample rate is sufficient by stopping the waveform, zooming in on it, and finding that if the waveform changes (e.g., some amplitude), the sample rate is insufficient, otherwise it is fine. You can also use the dot display to analyze whether the sample rate is sufficient.
