Sample Indexing Modulation
Sinha, Rohit Kumar · ASME Press eBooks · 2012
In Sample Indexing Modulation (SIM), a message signal is sampled, and each set of seven samples is considered as a frame. Each sample in a frame has a sample number which is 1 to 7(3bit ). A frame is stored in a RAM giving the sample magnitude as the address and the sample number in the data field. Each frame starts with a flag. Time difference between arrival of the flag and the sample at the receiver determines the amplitude of that particular sample. Thus instead of 8 bits (as in PCM) only 4 bits are required for transmitting a sample, and a flag per frame. This reduces the bandwidth requirement. Reduced bandwidth requirement can allow service providers to serve the users with advanced services.