Designing the PC-Based 4-Channel Digital Storage Oscilloscope by using DSP Techniques

Nowadays, the digital storage starts to replace analog type oscilloscope due to the better functionality and features. Digital storage oscilloscope (DSO) is a device used by engineers, scientist or engineering students to verify or check the electronic circuit operation where the displayed signal in the DSO monitor can be analyzed and saved for future reference. DSO uses an analog-to-digital converter (ADC) to convert the electrical voltage or current being measured into digital form at certain sampling time. The sample of the signal will be saved and accumulated until it able to describe a waveform and reassembles the waveform for viewing in on the monitor screen. The purpose of the research is to design the PC-based 4-channel oscilloscope where the electrical signal being measured will be displayed on the PC (personal computer) monitor equipped with functionality button shown in term of Window based GUI (graphical user interface). The GUI is developed by using Microsoft Visual C++ 6.0. The PIC (peripheral interface controller) is used for data acquisition which transfers the data being measured to PC through RS232. Here 4 built-in ADCs are used in order to produce 4 channels Oscilloscope. The PIC is programmed by using C language to read the data from ADC and then transfer the data to PC. Frequency of 5 kHz is used as a sampling rate. Meanwhile, the clock speed of 20 MHz is selected in order to reduce the power consumption and noise. In addition, 8 Kbytes RAM chip is used for storing purpose. The research outcome shows 3 types of waveforms such as Sinusoidal, Square and Triangular are displayed with the correct frequency and amplitude. It is tested by using signal generator as an input to produce the waveform to the hardware. The integration between hardware (PIC) and software (GUI) is fully working. Beside that, the GUI is very user friendly and easy to be configured. The data from the signal being measured also can be saved and restored.