Posted 21 Dec 2010 06:14
In the field of electronic testing, the oscilloscope is the first test equipment, radar scans originated in the principle of the signal waveform acquisition and reproduction, from the traditional analog signal and analog circuit test basis. With digital technology, more and more important test of the digital signal, the first digital signal test, often by the oscilloscope, the subsequent emergence of a timing analyzer and state analyzer, from the perspective of timing and state analysis and test multi-channel digital signal. At that time, the timing analyzer and state analyzer is expensive, both in the market, the concept of good, but has little effect on the test range is very narrow. With the digital test technology development, integration of digital timing and state analysis of the logic analyzer application for us. From birth, the logic analyzer often gives the impression of three: expensive, operational problems; demanding of users; and oscilloscope functions similar, but more than some increase in the channel and timing functions. Essentially the logic analyzer and oscilloscope are both in the integration, but also test the principle was greatly different; coupled with the development of IT technology, computer-based interface technology and processing technology, virtual logic analyzer acquisition occurs, the logic analyzer has been gradually reducing the costs into the general laboratory, the same logic analyzer and oscilloscope testing has become a basic tool. Logic analyzer is to use the clock from the test equipment acquisition and display digital signals on the instrument, the main role is to determine the timing. Unlike the logic analyzer oscilloscope that there are many voltage levels, usually show only two voltage (logic 1 and 0), so set the reference voltage, the logic analyzer will be tested by comparing the device to determine the signal, higher than the reference voltage by the High, who is below the reference voltage Low, High and Low in between the digital waveform. For example: the signal being measured using a 200MHz sampling rate of the logic analyzer, when the reference voltage set to 1.5V, the logic analyzer in the measurement will take a point every 5ns, who is more than 1.5V High (logic 1) lower than those for the 1.5V Low (logic 0), then the logic 1 and 0 can be connected into a simple wave, engineers can find out in this continuous waveform exception error (bug) of the Department. Overall, the logic analyzer to measure the signal when the voltage is not shown, but the difference between High with Low; If you want to measure the voltage to a certain need to use the oscilloscope. In addition to the display of the different voltage, the logic analyzer and oscilloscope Another difference is that the number of channels. Generally only 2-channel oscilloscope or 4 channels, while the logic analyzer can have from 16 channels, 32 channels, 64 channels and hundreds of channels ranging from, so the logic analyzer with simultaneous multi-channel test advantage. According to differences in hardware design, logic analyzers currently on the market can be broadly divided into two independent (or stand-alone type) to be combined with logic analyzer and the computer's PC-based virtual logic analyzer card. Logic analyzer is a stand-alone test all the software, computing, and integration of management components into a single instrument; card virtual logic analyzer used in conjunction with a computer is required, the display also with the host separately. The overall specification, the independent logic analyzer has been developed to a high standard of products, such as sampling rate of up to 8GHz, the number of channels can be expanded to over 300 channels, the storage depth is also relatively high, stand-alone price of the logic analyzer in the past expensive, the number of one hundred thousand yuan from the tens of thousands to varied, the average user rarely afford. Taiwan Technology Co., Ltd. recently launched OLA2032BTM OItek independent desktop EasyDebugTM logic analyzer, not more than 20,000 yuan economic price so that each engineer can afford. Especially in the teaching of digital circuits, changing the past teachers used to reduce the cost of generating a virtual logic analyzer and thus is not intuitive, trouble and other issues, in the same price, we can separate the logic analyzer desktop easily picked up to. Computer interface card based on a virtual logic analyzer with a smaller cost of providing the corresponding performance, but a virtual logic analyzer card also has a great disadvantage, it needs to use with computers, especially digital test, engineers often find a pile of PCB board, the use of rotary instruments than on-screen buttons to move the mouse more convenient. Technology gradually to the oscilloscope and logic analyzer functions together, a hybrid instrument (MSO), also known as mixed-signal test equipment. Logic analyzer and oscilloscope is as follows, so we will know under what circumstances to use a logic analyzer or oscilloscope.