(a)[2]
State the purpose of the parallel-to-serial converter.
(b)
A section of the microphone signal is shown in Fig. 12.2.
(b(i))[1]
Determine the four-bit digital number output by the ADC at $0.4\,\text{ms}$.
(b(ii))[1]
Determine the four-bit digital number output by the ADC at $0.8\,\text{ms}$.
(c)[4]
The digital signal is sent and then changed into an analogue form by the DAC (digital-to-analogue converter). Using data from Fig. 12.2, draw, on the axes of Fig. 12.3, the output level of the transmitted analogue signal for time zero to time $1.2\,\text{ms}$.
(d)[3]
State and explain how increasing both the sampling frequency and the number of bits in each sample, for the ADC and the DAC, affects the transmitted analogue waveform.