Abstract: Method and apparatus for synchronizing a transmitter and a receiver in a synchronous serial transmission system by serially transmitting a plurality of pseudorandom, coded sync words in an interlaced fashion with corresponding bits of each word transmitted in sequence. At the receiver, received bits are first directed to a plurality of registers to undo the interlacing process and then decoded with the decoded word being compared by an autocorrelation technique to a known reference to thereby establish or reestablish synchronization between transmitter and receiver.

Abstract: An automatic meter reading and control system for communicating with remote terminal points includes a central station which selectively communicates with a transponder controller unit at each terminal point via a plurality of distribution units, each serving several transponder controller units. The distribution controller units are responsive to various commands issued by the central station to selectively route the commands to specified transponder controller units to direct the transponder controller units to selectively carry out a load control operation, a meter reading operation or transfer of previously stored meter data from the transponder units to the central station in accordance with functions specified by the various commands.

Abstract: A method for transmitting information with a desired bandwidth while suppressing interference due to harmonics of a system-wide signal, by transmitting each bit of information as a pair of spaced rectangular envelope modulation pulses having a time interval therebetween essentially equal to the reciprocal of the difference between the frequencies of a carrier and of adjacent harmonics of the undesired system-wide signal. A sequential plurality of double-pulse modulating waveforms can be transmitted for reception by a receiving means having a like plurality of demodulators each synchronized and sequentially enabled only when one of the pair of modulating pulses are present. A novel double-pulse demodulator means, capable of essentially rejecting undesirable harmonics in a system utilizing a data carrier modulated to be interlaced between sequential harmonics of a system-wide signal, and novel means for synchronous gating thereof, are disclosed.

Abstract: A digital communications system of the type transmitting data on a plurality of modulated FDM carriers interspersed between harmonics of a system-wide signal and utilizing a main synchronized detector at a receiving end, is immunized to signal degradation due to reception of "noise" from both the shifting of signal harmonics and the modulation sidebands of adjacent carriers into the passband of the desired communications signal during at least synchronization acquisition by methods of interference minimization including: emplacing each data carrier at a frequency mid-way between adjacent harmonics; locking the frequency of the data carrier to the system-wide signal frequency to maintain the communications frequency exactly mid-way between two adjacent harmonics of the latter signal; transmitting the data in digital form and modulating each data carrier at a baud essentially equal to an exact even submultiple of the system-wide potentially-interfering signal, and detecting the transmitted digitally-modulated c