On-line laboratories for speech and image processing and for communication systems using J-DSP

J-DSP is a Java-based object-oriented programming environment that was developed at Arizona State University for use in the undergraduate DSP class [A. Sapnias et al., June 2000]. In this paper, we describe innovative software extensions on J-DSP to accommodate on-line laboratories for speech processing, image processing, and communications systems. Significant modifications in the object-oriented GUI of J-DSP that enable simulation of feedback systems are also presented. The speech processing functions enable on-line simulations of speech coding algorithms and include PCM and ADPCM quantization as well as more elaborate algorithms such as the LPC and the CELP. Image processing functionalities include development of 2-D signal processing capabilities including 2-D-FFT, 2-D-filter design, and 2-D graphics and picture processing. Communications functionality covers several aspects of analog and digital modulation and demodulation. On-line laboratory exercises have been developed in the aforementioned areas and posted on a web site (http://jdsp.asu.edu). This site also includes on-line evaluation forms for the exercises. Statistical and qualitative evaluations that assess the learning experiences of the students that use J-DSP are presented.