Physics 9702 · AS & A Level · Characteristics of alternating currents
Characteristics of alternating currents — practice question
Fig. 5.1 shows how the voltage level of part of an analogue signal changes as time $t$ passes. Sampling is carried out at $0.25\,\text{ms}$ intervals, and each sample is then turned into a four-bit digital number. Fig. 5.2 gives several values of time $t$ at which the voltage level is sampled. The digital number at time $t = 0$ is shown.
(a(i))[1]
On Fig. 5.2, underline the most significant bit (MSB) of the digital number at time $t = 0$.
(a(ii))[2]
Complete Fig. 5.2 using the times shown.
(b)[3]
Once the digital numbers have been transmitted, the signal passes through a digital-to-analogue converter (DAC). On Fig. 5.3, plot the analogue signal produced by the DAC.
(c)[4]
The transmitted signal in (b) is less detailed than the original signal in Fig. 5.1. Suggest and explain two ways in which the level of detail in the transmitted signal could be improved.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Binary numeral 1011” …