초록 ▼

A communications system wherein an intelligence signal modulates the spacing of relatively narrow pulses of a fixed rate pulse train, and these pulses key on a transmitter which employs a pair of series connected avalanche mode operated transistors. These are repetitively powered via a charged coaxi

A communications system wherein an intelligence signal modulates the spacing of relatively narrow pulses of a fixed rate pulse train, and these pulses key on a transmitter which employs a pair of series connected avalanche mode operated transistors. These are repetitively powered via a charged coaxial delay line, and the output, appearing across a resistive load, is fed directly, or through a shaping filter, to a discone transmitting antenna. At a receiving location, the received signal is amplified by a wide band amplifier and fed through a reverse contoured filter (of the transmitting filter, if one is employed). The signal is detected via synchronous detection which locks onto the received pulse train, after which the modulation evidence by the pulse train is recovered by a low pass filter.

대표청구항 ▼

A spread spectrum radio transmission system comprising: a radio transmitter comprising: pulse generating means for generating reoccurring pulses, said pulses appearing at a selected time spacing, a source of intelligence signals, and modulation means responsive to said pulses generating means and sa

A spread spectrum radio transmission system comprising: a radio transmitter comprising: pulse generating means for generating reoccurring pulses, said pulses appearing at a selected time spacing, a source of intelligence signals, and modulation means responsive to said pulses generating means and said source of intelligence signals for providing as an output a train of pulses wherein the leading edge of pulses is varied in time position as a function of intelligence signal; avalanche semiconductor switching means, having a control signal input responsive to said output of said modulation means, a bias power input, and a switched power output, for switching power on and off to said switched power output; a D.C. bias source coupled to said bias power input comprising a delay line having a delay of 1 picosecond to 50 nanoseconds and delay line charging means coupled to said delay line for charging said delay line between pulses of said train of pulses; transmitting antenna means comprising an aresonant antenna coupled to said switched power output and to space for transmitting a signal received from said switched power output; and a radio receiver comprising: receiving antenna means comprising an aresonant antenna for receiving transmissions from said transmitting antenna means and for providing as an output electrical pulses responsive to the transmitted pulse signals, amplification means responsive to the output of said receiving antenna means for amplifying received pulses, synchronous detection means, including signal sensitive windowing means having a signal input responsive to the ouput of said amplification means, for responding to, and providing an output for, signals appearing within reoccurring windows of time generally coincident with the average time of occurrence of pulses received by said receiving means and including means for being insensitive to received signals appearing between the occurrence of said windows of time, signal conversion means for converting the output of said detection means into a replica of signals of said intelligence signals, and signal reproduction means responsive to the output of said signal conversion means for reproducing said intelligence signals.