"origiral" - 1 õppematerjal

Mikrokontrollerid ja praktiline robootika

b) Name another disadvantage of such a mixer circuit. Solution: a) Because the mixer outputs become four (4) including the two input frequencies, the sum and the difference of them. Actually we need only the difference output frequency (Offset – Input) and the lowpass filter will help to filter aways the higher three output frequencies. b) Name another disadvantage of such a mixer circuit (page 97-98) - The mixer multiplies the wanted frequency shift but also other frequency shifts (origiral, sum, etc.). This includes noises and heating. - If the input frequency comes down and the difference frequency will increases up and may be filtered aways by the low pass filter. - The design of the mixer is complecated. - The circuit may produce more ElectroMagnetic Interference (EMI) Question 4 (10 marks) Consider the following circuit and input waveform. Draw an equivalent output waveform. Solution: Question 5 (20 marks)