HOW TO USE A PC OR USB OSCILLOSCOPE......(CLICK HERE)
SAMPLE RATE/SAMPLING: When the shape or detail of a signal is important, sampling rate is prime consideration when selecting a oscilloscope to capture that signal. The easiest way to think of Sample Rate or Sampling is to envision a movie film. The film is made up of a large number of frames. Each frame is a still picture of the action. Typical or normal film speeds "sampling" is 24 to 30 frames per second. When shown one after the other, in sequence, events move along at a normal pace. Now think of taking a pictures of a football play or NASCAR Crash, to see real detail of what is happening with a movie camera we must take pictures at a faster rate, say 100 to 1000 frames per second to see what is happening in great detail. We do this because the action taking place is happening at such high speed that at normal pace of filming much of the detail would be lost.
Back to electronics, you must take a picture of signals you want capture two times per cycle to be able to identify its frequency. An example, if the frequency of interest is 10 cycles per second (10 Hertz) then you must sample at 20 times per second minimum. Taking more pictures of the signal each second gives more detail of the signal. See FREQUENCY below.
AMPLITUDE/BITS. Where the height or amplitude of the signal is important, such as audio work, then bit rate is important. This relates to the precision or each measurement (resolution). As the bit rate increases from 8 bits to 12 bits the resolution increases16 times (256 to 4096) and from 12 bits to 16 bits (4096 to 65,536). Over a voltage range of 10 Volts the smallest voltage you can measure with accuracy with 8 bit resolution is 0.039 Volts/39 millivolts, (10/256). That same signal can be measured accurately to 0.00244 Volts/2.44 millivolts (10/4096)with 12 bit resolution and .000153 Volts/0.153 millivolts (10/65,536) with 16 bit resolution.
FREQUENCY. Frequency is cycles per unit time. In electronics this is normally is cycles per second or called Hertz (a tribute to a scientist that did a lot of work in frequency determination and mathematics). The frequency of the signals that you want to measure can be no more than one-half the sample rate of the oscilloscope that you will use. SAMPLE RATE is normally stated as the "speed" of the scope in Megahertz (Millions of samples per second) or Kilohertz (Thousands of cycles per second). If the shape of the signal is very important to you the sample rate should be no less than 5 times the highest frequency of interest. If the highest signal of interest is no more than 2MHz and the shape of the signal is important then a PC Oscilloscope of no less than 10MHz is needed, preferably 20MHz or more is desired
Electronics use of oscilloscopes often require higher speeds that other types of measurements, especially where communications are involved. Low speed electronics or equipment often used for mechanical control or interface may not require a lot of speed.
Audio oscilloscopes typically will tend toward slower speeds and higher bit rtes (16 bits) for precision measurements.
Mechanical systems can make wonderful use of PC oscilloscopes in the measurement of many different types of sensors. relatively slow frequency scopes with 12 and 16 bit resolution can be great analysis tools. The PicoScope line of automotive oscilloscopes are all 12 bit scopes and do an exception job in assisting the mechanic in doing mechanical as well as electrical analysis. We have used these scopes for machine monitoring and physical dynamic balancing of mechanical systems.