Show which of the following statements about the amplitude limiter is untrue: When the input increases past the threshold of the limiting, the gain decreases to keep the output constant. The output must be tuned Leak-type bias must be used The circuit is always biased in class C, by virtue of the leak-type bias. TRUE ANSWER : ? YOUR ANSWER : ?
In a ratio detector the circuit is the same as in a discriminator, except that the diodes are reversed the output is twice that obtainable from a similar phase discriminator stabilization against signal strength variations is provided the linearity is worse than in phase discriminator TRUE ANSWER : ? YOUR ANSWER : ?
The frequency generated by each decade in a direct frequency synthesizer is much higher than the frequency shown; this is done to Reduce the spurious frequency problem Reduce the number of decades Increase the frequency stability of the synthesizer Reduce the number of crystals required TRUE ANSWER : ? YOUR ANSWER : ?
A low ratio of the ac to the dc load impedance of a diode detector results in Diagonal clipping Poor AF response Poor AGC operation Negative-peak clipping TRUE ANSWER : ? YOUR ANSWER : ?
One of the following cannot be used to demodulate SSB: Product detector Complete phase-shift generator Diode Balance modulator Bipolar transistor balanced modulator TRUE ANSWER : ? YOUR ANSWER : ?
If a FET is used as the first AF amplifier in a transistor receiver, this will have the effect of Reducing the effect of negative-peak clipping Reducing the effect of noise at low modulation depths Improving the selectivity of the receiver Improving the effectiveness of the AGC TRUE ANSWER : ? YOUR ANSWER : ?
An AM receiver uses a diode detector for demodulation. This enables it satisfactorily to receive Single-sideband, suppressed-carrier Single-sideband, reduced-carrier ISB Single-sideband, full-carrier TRUE ANSWER : ? YOUR ANSWER : ?
The controlled oscillator synthesizer is sometimes preferred over the direct one because It is a simpler piece of equipment Its frequency stability is better It is relatively free of spurious frequency It does not require crystal oscillator TRUE ANSWER : ? YOUR ANSWER : ?
In a broadcast superheterodyne receiver, the Mixer input must be tuned to the signal frequency Local oscillator operates below the signal frequency Local oscillator frequency is normally double the IF RF amplifier normally works at 455 kHz above the carrier frequency TRUE ANSWER : ? YOUR ANSWER : ?
One of the main functions of the RF amplifier in a superheterodyne receiver is to Improve the rejection of the image frequency Increase the tuning range of the receiver Permit better adjacent-channel rejection Provide improved tracking TRUE ANSWER : ? YOUR ANSWER : ?