The original ASCII table is encoded on 7 bits and extended ASCII table uses 8-bit representation. However, in this example as the text doesn't contain any extended ASCII characters 7 bits are used.
Follow the steps to find out the bit representation used:
- Go to the Simulink model of QPSK Transmitter.
- Double click on the bit generation block.
- Look at the properties of "Signal from Workspace" block.
- A parameter named "Samples per frame" will contain the information on number of bits transmitted.
You can try changing the bit representation to 8 bits by editing the 'Samples per frame' parameter.
The length of the text is not 15, it will be 16 which includes the end character.
length = 16;
ASCII_bit_representation = 7;
thats '16*7 = 112 bits/message'.
no_of_messages = 20;
no_of_bits = 20*112 = 2240 bits.
Hope this resolves your problem.
