Consider a biomedical application which uses the real$-$time ECG of a patient to predict the occurrence of Cardio$-$Vascular ailments. The frequency of the ECG signal ranges from $0\mathrm{.}5$Hz to $100$Hz$.$ The sensor produces an output voltage of $0\mathrm{.}5$ mV to $5$ mV$,$ with a DC component of $1$V due to its placement and the potential between the electrodes and ground. The ECG signal may be corrupted by power$-$line interference. This signal has to be fed to an ADC which works on a maximum voltage of $5$V$.$ Given this requirement, answer the following questions:

i$)$ The activity of the human heart can be measured by using more than one physical phenomenon. Mention at least $2$ physical phenomena that are of use here. Justify. $(4$ marks$)$

ii$)$ What are the signal conditioning blocks that are required on the path of the signal from the sensor to the ADC? Mention rough specifications of these blocks, and justify their need. $(6$ marks$)$

iii$)$ What should the sampling rate of the ADC be$?$ Justify. $(2$ marks$)$

iv$)$ If the required quantization noise is $0\mathrm{.}5$mV$,$ what should the resolution of the ADC be and consequently the number of bits needed for the conversion? $(4$ marks$)$

v$)$What are the potential errors that the ECG sensors can have? How can they be corrected? $(4$ marks$)$