a signal that causes a variation of some of the properties of the carrier.

unmodulated signal that suits a particular application.

when you vary the amplitude of the carrier in proportion to the information signal.

when you vary the frequency of the carrier in proportion to the information signal.

·          coefficient of modulation, the ratio of the magnitudes of the modulated signal & the unmodulated carrier.

These sidebands also carry information being transmitted by an electronic communication device resulting to a________

·          is the operating frequency or the center frequency of a certain communication medium which is used to modulated a baseband frequency or information from the sender.

·          the information signal modulates the RF carrier signal to produce a modulated waveform made up of many frequencies

The ability of a resonant circuit to maintain oscillation at an essentially constant frequency when fed with short pulses of energy

-           a sensitive, class A, linear voltage amplifier with high input impedance which raises the amplitude of the source signal to a usable level with minimum nonlinear distortion & little thermal noise as possible

-           commonly uses crystal-controlled units to generate the carrier signal for accuracy & stability

-           the circuit which translates the information signal to frequencies appropriate for transmission

-           a low-gain, high-input-impedance linear amplifier which isolates the oscillator from the high-power amplifiers

This part of the transmitter, exclusive of the power handling stages, is called the_________

·          Each AM station is allocated a frequency band of _________ in which to transmit its signal.

1.         ability to drive the output transducer to an acceptable level 2

ability to differentiate between the desired signal and unwanted signal

·          is a compromise between DSB and SSB.

a wideband RF amplifier which is the first stage of the receiver. Often called the receiver front end; it is mechanically tied to the local oscillator to ensure precise tuning characteristics. It performs the detection, band limiting, & amplification of the received RF signals.

1.         a variable oscillator which provides a signal at a certain frequency which, when combined with the received RF signal at the mixer stage, produces a group of frequencies which includes the intermediate frequency.

tuning the local oscillator frequency above the RF signal by an amount equal to the intermediate frequency.

·          tuning the local oscillator frequency below the RF signal by an amount equal to the intermediate frequency.

1.         a class C nonlinear device which comes after the RF stage. It processes the received RF signals, producing the sum, difference, and original RF frequencies. The difference frequency is equal to the intermediate frequency & will serve as the input to the succeeding stage.

a very narrow bandwidth class A device which receives the down converted RF signal & filters the unwanted frequency components to prevent them from being demodulated with the original information signal; this section produces an amplified signal at the output & determines the sensitivity & selectivity of the receiver

one of the simplest and most effective types of detectors, and one with nearly an ideal nonlinear resistance characteristic

a system in which the overall gain of a radio receiver is varied automatically with the changing strength of the received signal to keep the output substantially constant. It enables tuning to stations of varying signal strengths without an appreciable change in the volume of the output signal, expect when the change in signal strength is enormous.

a system in which the overall gain of a radio receiver is varied automatically with the changing strength of the received signal to keep the output substantially constant. It enables tuning to stations of varying signal strengths without an appreciable change in the volume of the output signal, expect when the change in signal strength is enormous.