CONTENTS -- HISTORICAL BACKGROUND - Meaning of modulation; historical note; speed of signaling; Nyquist interval; Hartley's expression for information capacity; Contemporaneous developments; WHY MODULATE - to prepare the message for transmission; to translate signals from one medium to another; to prepare the received signals for their destination; to convey messages from one point in space-time to another;

KINDS OF MODULATION - amplitude modulation; usage of terms sinusoidal wave & sine wave; extension of meaning; angle modulation; PM & FM; pulse modulation; pulse-code; topics not treated; SAMPLING PRINCIPLE - special statement of; samples of nonzero duration; generalized treatment; additional theorems pertaining to periodic sampling of signals; Refs & Problems; QUANTIZATION, CODE TRANSMISSION & MULTIPLEXING;

EFFICIENT SYSTEMS OF COMMUNICATION - interference threshold as a function of band width; tables of probabilities & distribution of voltages in speech, etc; SPEED OF SIGNALING & CHANNEL CAPACITY - in the absence of noise; signaling at Nyquist rate in presence of noise; MacColl's proposal for rapid signalling; more; REDUCTION OF SIGNAL POWER THROUGH THE USE OF REDUNDANT CODES - qpplication of error-correcting codes to one-way systems of communication; error correction using both directions of transmission; more;

AMPLITUDE MODULATION - noise & interference; more; AMPLITUDE MODULATORS & DEMODULATORS - transmission distortion etc; AMPLITUDE-MODULATION SYSTEMS - carrier & both sidebands; reduced carrier; single sideband; vestigial; Day's system, more;

FREQUENCY MODULATION - FREQUENCY MODULATORS & DEMODULATORS; NOISE & INTERFERENCE IN FM SYSTEMS; PULSE-MODULATION ESSENTIALS; PULSE-AMPLITUDE MODULATION; PULSE-DURATION MODULATION; PULSE-POSITION; PULSE-CODE PCM; MOBILE PULSE-MODULATION SYSTEMS synchronous nonsynch etc. MORE