How to generate a 10-bit digital signal of given 10 digits?

Given code:

Am=5; % Amplitude of modulating signal

fa=300; % Frequency of modulating signal

Ta=1/fa; % Time period of modulating signal

Ts=Ta/80; % Sampling interval

t=0:Ts:(10*Ta-Ts); % Total time for simulation

ym=Am*cos(2*pi*fa*t); % Equation of sinusoidal modulating signal

figure(1)

subplot(4,1,1);

plot(t,ym), grid on; % Graphical representation of input modulating signal

title ( ' Input Modulating Signal ');

xlabel ( ' Time (sec) ');

ylabel (' Amplitude (volt) ');

My Question:

1. How to modify the program code of the “Input modulating signal” (line 6) to

generate a 10 bit digital signal , which the 10 digits are "1234567890"

with each digit spans for a period of Ta .

(The resultant code will be assigned to the variable ym.)

2. How to use the MATLAB functions ones(1,n) to generate your resultant

code?

3. What is the required number of repetitions for each digit in terms of Ta (digit period) and Ts (sampling period). The amplitude of each bit will be corresponding to the value of the respective

digital (123467890).

Thank you for answering my questions and showing me the new code for ym. ^_^

Answer 1

[Kevin Barkett]

Hi there,

If I'm understanding your question correctly, what you are attempting to do is create an array for the variable which returns something like 'ym = [ 1 1 ... 1 1 2 2 ... 2 2 3 3 ....... 0 0 ];'

One way you create that from the variables you've defined above is:

ym = mod(floor(t/Ta)+1,10);

By using 'floor(t/Ta)', this creates an array of numbers partitioned between intervals evenly spaced by the period 'Ta' with each element in a partition numbered according to which period it occurs in. The rest of the function is to shift the array to the desired values for each interval. Since computing 'ym' in this way sets it with the same array extents as 't', I am unsure why it is necessary to use the 'ones(1,n)' function.

Using the definition given for 'Ta' and 'Ts', the number of elements in the array across each interval of 'Ta' (and thus the number of repetitions of each digit) can be obtained

numberOfSamples = Ta/Ts;

since that corresponds to how many distinct sampling intervals occur over the entire period.

Cheers,

Kevin