In this assignment, the aim is to question whether there is a frequency of 290Hz in a composite signal containing multiple sine components. 290Hz exists in a certain period of time and then disappears. Therefore, the existence of frequency will be questioned in a continuous loop. The analog signal is converted to digital and comes from the 8051 serial port to C. Therefore, data belonging to the analog signal is constantly coming from the serial port. The amplitude of the composite signal varies between -1 / + 1 and the signal is quantized with 8 bits in the ADC. When querying for the presence of the sign, you can set the threshold value to a quarter of the value -1 / + 1. When the presence of the signal is detected, a 5 second sound will be generated from a "buzzer" connected to the parallel port.

- To achieve this goal, an IIR filter or DFT algorithm must be written. - In DFT use, the external variable k must be converted to frequency. X (k) = DFT (x (t)) in this equation, k is an integer from 0 to half the window width. You must switch from this integer to frequency. Because you will be interested in the change in your own frequency. - Interrupts will be used for timer and serial port.

a) Draw the flow diagram of the algorithm. b) Write the c program.