You will design a data-acquisition system to measure force. The range of force is –10 to 10 N. The force signal exists in the 0 to 99 Hz frequency band. You will measure the ADC at a fixed rate, convert each sample to signed decimal fixed point, and write each fixed-point measurement into global variable called Force (which is the integer part of the fixed-point number). The ADC sampling must occur in real-time using an output compare periodic interrupt Channel 5.

a) Choose the sampling rate. Explain why you chose that value.

b) The sensitivity of the bridge output is 0.025 V/N, meaning the differential voltage (V2-V1) varies from –0.25 to +0.25 V. However, both V1 and V2 are around 2.5 V (more specifically V2 varies from 2.375 to 2.625 V, while V1 varies from 2.625 to 2.375 V). A good CMRR is required. Design the analog circuit mapping the bridge output into the ADC input Channel 3. (You do not have to add an antialiasing analog low-pass filter.) Show chip numbers, resistor values, but not pin numbers.

c) Assuming the only error occurs in the 10-bit ADC, what is the expected force measurement resolution in Newtons (N)?

d) Write the entire program that implements this real-time data-acquisition system. You are allowed to call the following functions (without showing the implementations of these functions).

If you need other functions, you will have to show their implementations. Be sure to include the software that maps unsigned ADC (0 to 1023) into a signed fixed point (resolution you choose in part c). Include the output-compare 5 initialization and ISR.