Looking for a cheap digital storage oscilloscope? How to turn existing PC into a powerful PC oscilloscope?




Digital Storage Oscilloscope (DSO) is an indispensable tool to analyze complex signals or debug electronic devices. Because the signals are sampled and stored into memory it is very easy to examine them and their relations. DSO is in fact a special computer with many fast A/D converters and software to analyze and display signals. With DSO the problem of displaying short-time signals and glitches is history. It only depends on your settings and trigger conditions to capture the right moment. Storage capacity is rarely problem unless you would like to store longer intervals.




Because of the computer-based design of the DSO it is pretty simple to convert ordinary PC into a DSO. PC Based digital storage oscilloscope is in fact software which runs on a PC with suitable interface for analog signals. This interface is usually a small box with fast A/D converters connected to the parallel or USB port. PC based oscilloscopes have many advantages over classical DSOs. Since the capabilities of the software are limited only by the interface and computer resources it is possible to track many channels in real time, analyze FFT spectrum or decode buses like SPI, I2C, JTAG or UART.


The physical limitations of a PC oscilloscope are mainly defined by the external hardware that is used to sample analog or digital signals. The main parameters that define PC DSO capabilities are number of channels, bandwidth, sample rate and sample memory size. The sampled data is stored into buffer from where it is transferred to the PC where it is analyzed and displayed. Therefore, at least in principle the buffer needs only to be large enough to store samples until they are transferred to the PC. Only in principle because the parallel port is not fast enough to transfer huge amounts of data in real time.


A big advantage of PC based oscilloscopes is upgradeability of the software. You simply install new version and you get bugs fixed or new functionality. Some PC oscilloscopes also allow you to write your own plugins for custom decoding. The average price of PC oscilloscope is significantly lower than the price of a real DSO but it is still higher than the price of the PC where it will run. Nevertheless, PC DSO is a compact, cheap and universal solution for hobby or professional electronics laboratory. It allows you to analyze arbitrary signals, to decode popular serial protocols and to store signals for later processing.

BitScope

BitScope is a USB or Ethernet device which can convert any personal computer into powerful PC based Mixed Signal Oscilloscope. You can sample 4 analog and 8 digital signals at the same time. BitScope can be used as a digital storage oscilloscope, logic analyzer, spectrum analyzer and data recorder. With some models you can also generate arbitrary waveforms with built-in waveform generator.

PicoScope

Pico Technology is another top manufactures of PC based data acquisition devices. Their PicoScope line of PC based oscilloscopes includes everything from cheap single channel versions with 20 M samples/s to high-end 4-channel 5 G samples/s oscilloscopes. All PicoScope oscilloscopes function as a professional digital storage oscilloscope and include also spectrum analyzer functionality and data logging software.

USBee

USBee is more than a PC based oscilloscope. It is also a powerful logic analyzer and protocol analyzer. Their line of USB devices includes cheaper models for hobby engineers and professional PC oscilloscopes for demanding industry needs. Some models include also digital signal generator.

TiePie

TiePie is a Dutch company developing data acquisition devices and PC based oscilloscopes. They offer USB devices and PC cards for oscilloscope, transient recorder, spectrum analyzer, logic analyzer and multimeter functions. Some TiePie models also include an arbitrary waveform generator.

Acquitek

Acquitek is a French manufacturer of data acquisition products and USB instrumentation. Their top USB oscilloscope supports up to 4 Channels with up to 7G S/s and 8, 10, 12 or 14-bit resolution. Cheaper versions are available for hobby developers.

I2C analyzer

A special version of PC based oscilloscope is the I2C analyzer. This is a simplified device which samples few channels and decodes I2C, SPI, UART and other popular protocols. An important function is the I2C host adapter mode which allows you to send I2C or SPI packets and act as a master device. I2C analyzers are much cheaper then PC based digital storage oscilloscopes and many such devices can also be used as a logic analyzer with basic functionality.