Digital oscilloscopes from various manufacturers appeared on the market, so choosing an instrument was a daunting task for an engineer. The cost of a digital oscilloscope depends on its versatility and the parameters of individual characteristics. Do not rely only on the price of the device, because you run the risk of being left without measurements of the range you need. First, identify the maximum needs of your job.
Instructions
Step 1
Think about the amount of bandwidth you need. For the most accurate amplitude measurements, select an oscilloscope bandwidth that is an order of magnitude greater than the fundamental frequency of the signal being measured. Even for less accurate measurements, select an oscilloscope bandwidth three times the signal frequency. This also applies to measurements of time signals. After all, the greater the ratio of the parameters of the signal front and the actual front of the oscilloscope, the smaller the error will be.
Step 2
Determine how many channels you will be using. If you anticipate that you will need to capture signals on two or three channels at the same time, then give preference to a parallel-triggered oscilloscope or a separate ADC for each oscilloscope channel. If you are examining signals that are repeated, then you do not need to simultaneously receive data through the channels.
If 4 channels are not enough for you, then it is advisable to purchase a logic analyzer.
Step 3
Decide on the required sampling rate. Higher sampling rates translate into a wider bandwidth when working with single-shot signals, resulting in better resolution. In some oscilloscopes, the sampling rate can be adjusted by the operator, and the amount of information displayed on the oscilloscope display remains independent. Be careful, the sampling rate indicated in the manual can characterize only one channel.
Oscilloscope memory is limited in size, so the sampling rate decreases at a slow sweep speed.
Step 4
Calculate the amount of memory you need. The amount of memory is equal to the ratio of the time span in seconds to the resolution in seconds. The increased amount of memory will greatly slow down the response of the oscilloscope to your actions and to changes in the input signal.
Step 5
Think about the triggering capabilities you need. In most cases, a front trigger is sufficient. Look for additional launch options to meet your complex challenges. For example, triggering by a combination of logical states across instrument channels.
Step 6
Consider the factors that affect the oscilloscope's ability to detect impulse noise and the signal analysis capabilities you require.
