A fair number of (USB) oscilloscopes have previously been reviewed and tested. However, the SmartScope is a measuring instrument that differs significantly from the competition, in both hardware as well as software. Before we take a closer look at the SmartScope, Let's find out how this project started.
When electronic engineer Riemer Grootjans acquired a number of different USB scopes for use at work and at home, he wasn’t pleased with these devices. Hestarted to think about designing one himself, which would have all the features he expected of a USB scope: versatile, portable, easily extended, and with an intuitive user interface.
And he started...
About the Hard Stuff
The hardware for the SmartScope consists of a small metal enclosure (for good shielding), with a pair of full-sized BNC connectors on the front for the analog inputs, and a 16-pin header at the back, for the 8 digital inputs of the logic analyzer, 4 digital outputs, and the output of the built-in arbitrary waveform generator (AWG).
Also on the back are a mini and a micro USB connector. The mini-USB is for connecting to a tablet, smartphone or computer, the micro-USB is used to connect an external power supply, or for daisy-chaining several SmartScopes together.
The printed circuit board contains a powerful Xilinx Spartan 6 FPGA, which takes care of the main tasks (such as processing the received measurement data and creating the AWG signal).
The conversion of the input signals is taken care of by an A/D converter with 100
Msamples/channel and a resolution of 8 bits. A RAM chip provides a buffer capacity of 4 Msamples/channel.
A PIC controller takes care of the communications with the computer via de USB connection. There are several relays and opamps at the inputs for the range and AC/DC selections. The bandwidth of the analog input section is 45MHz. This is
quite large compared to the sample frequency of 100Msamples/s. This was done on purpose in order to minimize the attenuation of the input signals as much as possible.
In next part (2 of 3) we will be covering the SmartScope Software.