Thread: help! sampling with pcm system

help!!

An analog signal x(t)=10cos(2π500t) is going to be quantized by a N-bit PCM encoding system. Also given the binary number is in sign and magnitude format.
(a) What is the lowest sampling frequency to correctly sample the original signal for the PCM system? What will be the sampling frequency if the waveform needed to be accurately sampled?

(b) If the PCM system is taking the truncation rule during quantization, and the quantization error can not be greater than 10mV, what should the lowest N be?

(c) Suppose N=9 and the rounding rule is taken now, what will be the binary and hexadecimal representation of the following input voltages?
i. 3V
ii. -2.5V