Subelement F: Receivers— Topic 44: Mixers
Question 3-44F4
Element 3 (GROL)What are the principal frequencies that appear at the output of a mixer circuit?
Explanation
A mixer circuit operates as a non-linear device, designed to combine two input frequencies (let's call them f1 and f2). Due to this non-linear interaction, new frequencies are generated at the output. The principal frequencies that appear are the two original input frequencies (f1 and f2), along with their sum (f1 + f2) and their difference (f1 - f2). These sum and difference frequencies are crucial for processes like frequency conversion in superheterodyne receivers.
Options A, B, and D are incorrect. Option A describes harmonics, which are multiples of a single frequency, not the output of combining two distinct frequencies in a mixer. Option B incorrectly includes "square root" as an output frequency. Option D refers to voltage ratios or constants, not frequencies generated by a mixer.
Related Questions
3-44F2 What is the mixing process in a radio receiver?3-44F3 In what radio stage is the image frequency normally rejected?3-44F5 If a receiver mixes a 13.8 MHz VFO with a 14.255 MHz receive signal to produce a 455 kHz intermediate frequency signal, what type of interference will a 13.345 MHz signal produce in the receiver?3-44F6 What might occur in a receiver if excessive amounts of signal energy overdrive the mixer circuit?3-45F1 What degree of selectivity is desirable in the IF circuitry of a wideband FM phone receiver?