Digital Signal Processing first transforms an analog signal to digital via an analog-to-digital converter (ADC), performs mathematical operations to filter or demodulate, for example, and recreates an analog signal through a digital-to-analog converter (DAC). Aliasing is a situation where input frequencies above the sampling rate get erroneously reproduced as lower frequencies; the situation is prevented through the use of an anti-aliasing filter (a low-pass filter).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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256 levels in binary data spans the range 0 to 255. Add the value of each bit in an 8-bit binary number, starting with the lowest: 1 + 2 + 4 + 8 + 16 + 32 + 64 + 128 = 255.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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The number of bits determines the maximum number of distinct values available to represent a signal. For each sample, the analog-to-digital converter selects the closest value to describe the instantaneous value of the input signal. The difference between the real value and its numerical representation is a quantization error: plus or minus half a bit, i.e., 1 bit total. In digital terms, Signal-to-Noise Ratio and Dynamic Range are synonyms specifying the ratio between the largest possible sample value to the quantization error. Dynamic Range for fixed-point processors can be approximated by the data word size: 6 dB times number of bits. Each bit doubles the value, doubling voltage is 6 dB.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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Digital Signal Processing first transforms an analog signal to digital via an analog-to-digital converter (ADC), performs mathematical operations to filter or demodulate, for example, and recreates an analog signal through a digital-to-analog converter (DAC). Aliasing is a situation where input frequencies above the sampling rate get erroneously reproduced as lower frequencies; the situation is prevented through the use of an anti-aliasing filter (a low-pass filter).

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none