Communication systems

Claim 3

The method defined in claim 1 which includes the step of utilizing initiating signals derived from said time marker signals for initiating generation of said intelligence signals.

Claim 4

The method defined in claim 2 in which sid intelligence signals are formed as pulses and in which said time marker signals comprises one edge of the pulse transmitted by said first station.

Claim 5

The method defined in claim 3 in which said pulses are formed as bursts of radio frequency energy, the pulses from the first and second stations being transmitted alternately and comprising bursts at a common radio frequency.

Claim 8

The invention defined in claim 5 in which said generation of both of said ramp forms is initiated at the same time.

Claim 9

The invention defined in claim 5 in which a start signal and a stop signal are generated at the time when said first ramp form and said second ramp form reach said first and second values, respectively.

Claim 10

The invention defined in claim 7 which comprises the further step of utilizing said start signal and said stop signal to key a radio frequency carrier wave on and off.

Claim 11

The invention defined in claim 8 in which stop and start signals are provided successively whereby there is produced a succession of bursts of radio frequency energy the time width of which is modulated in accordance with the degree in which the slope of said one ramp form is altered.

Claim 12

The invention defined in claim 9 which comprises the further step of modulating the time width of said bursts of energy to represent a digital code by altering the slope of one of the ramp forms such that the slope has one value to represent a zero and another value to represent a one.

Claim 13

The invention defined in claim 10 in which each burst of a series of bursts of energy is modulated in time width to represent one, respectively associated, bit of a series of bits representing a code.

Claim 16

An amplifier circuit comprising: a tuned circuit; a pair of transistors having their respective collector current carrying circuits connected in parallel between a common energy source connection and opposite ends of said tuned circuit; a third transistor having its collector current carrying circuit connected in series with said common energy source connection; each of said transistors comprising a control element effective in response to applied voltages to control current flow in its respective controlled current carrying circuit; and means for applying an input signal to one of said pair of transistors and to said third transistor simultaneously; the control element of the other of those transistors being maintained at uniform potential.

Claim 17

An amplifier circuit comprising: a tuned circuit; a pair of transistors having their respective collector current carrying circuits connected in parallel between a common energy source connection and opposite ends of said tuned circuit; a third transistor having its collector current carrying circuit connected in series with said common energy source connection; each of said transistors comprising a control element effective in response to applied voltages to control current flow in its respective controlled current carrying circuit; and means for applying an input signal to one of said pair of transistors and to said third transistor simultaneously; the control element of the other of those transistors being maintained at uniform potential.

Claim 18

The invention defined in claim 13 in which said tuned circuit comprises a center tapped coil and a capacitive reactance element connected in parallel with one another, the controlled current carrying circuit of each transistor comprising its collector-emitter circuit; and the centertap of said coil forming a second common connection for connection to an energy source.

Claim 19

The invention defined in claim 14 in which said means for applying an input signal comprises means for applying an input signal having substantially a given frequency and in which said tuned circuit is tuned to substantially that same given frequency.

Claim 20

In combination: generator means for generating first ramp shaped wave forms; means for detecting when each of said first ramp shaped wave forms has a given value; means for altering one of said given value and the slope of said ramp form as a function of the value of a modulating signal; means for generating second ramp shaped wave form; means for detecting when each of said second ramp shaped wave forms has a given value; means for altering, as a function of a second modulating signal, one of said given values of the second ramp shaped wave form and its slope; and means for generating time marker signals; the wave forms of one of said first and said second ramp shaped wave forms having a slope greater than the other, the wave forms of both ramp shaped wave forms being initiated at a time having a predetermined relation to said marker signals.

Claim 21

In combination: generator means for generating first ramp shaped wave forms; means for detecting when each of said first ramp shaped wave forms has a given value; means for altering one of said given value and the slope of said ramp form as a function of the value of a modulating signal; means for generating second ramp shaped wave form; means for detecting when each of said second ramp shaped wave forms has a given value; means for altering, as a function of a second modulating signal, one of said given values of the second ramp shaped wave form and its slope; and means for generating time marker signals; the wave forms of one of said first and said second ramp shaped wave forms having a slope greater than the other, the wave forms of both ramp shaped wave forms being initiated at a time having a predetermined relation to said marker signals.

Claim 22

The invention defined in claim 16 which further comprises: means for receiving bursts of radio frequency energy; detecting means for detecting the time, and providing a first signal when a burst first reaches a given amplitude; and means for detecting the time, and providing a second signal, when the amplitude of a burst first falls to a given amplitude.

Claim 23

The invention defined in claim 16 in which said first and said second modulating signals are analog signals.

Claim 24

The invention defined in claim 18 in which at least one of said first and said second modulating signals is a digital signal.

Claim 25

In combination: generator means for generating first ramp shaped wave forms; means for detecting when each of said first ramp shaped wave forms has a given value; means for altering one of said given value and the slope of said ramp form as a function of the value of a modulating signal; means for generating time marker signals; means for initiating generation of said first ramp shaped wave form at a time having a predetermined relation to said time marker signals; means for generating a radio frequency carrier signal; means responsive to detection of the time when each of said first ramp shaped wave forms has said given value for determining one edge of a burst of said radio frequency carrier signal; means for receiving bursts of radio frequency energy; detecting means for detecting the time, and providing a first signal when a burst first reaches a given amplitude; means for detecting the time, and providing a second signal, when the amplitude of a burst first falls to a given amplitude; said detecting means comprising a ring demodulator having first and second current inlets, the inlet currents of which have a given ratio at zero input signal and the first of which decreases, and the second of which increases, with increasing input signal; first and second current sources connected to supply current in a constant ratio of currents; the first current source being connected to supply a current less than zero signal current to said first inlet and said second current source being connected to supply more than zero signal current to said second inlet; and means responsive to reduction of input current to said first inlet to a value below that supplied by said first source to provide one signal and means responsive to increase of input to said second inlet to a value above that supplied by said second course to provide a second signal.

Claim 26

In combination: generator means for generating first ramp shaped wave forms; means for detecting when each of said first ramp shaped wave forms has a given value; means for altering one of said given value and the slope of said ramp form as a function of the value of a modulating signal; means for generating time marker signals; means for initiating generation of said first ramp shaped wave form at a time having a predetermined relation to said time marker signals; means for generating a radio frequency carrier signal; means responsive to detection of the time when each of said first ramp shaped wave forms has said given value for determining one edge of a burst of said radio frequency carrier signal; means for receiving bursts of radio frequency energy; detecting means for detecting the time, and providing a first signal when a burst first reaches a given amplitude; means for detecting the time, and providing a second signal, when the amplitude of a burst first falls to a given amplitude; said detecting means comprising a ring demodulator having first and second current inlets, the inlet currents of which have a given ratio at zero input signal and the first of which decreases, and the second of which increases, with increasing input signal; first and second current sources connected to supply current in a constant ratio of currents; the first current source being connected to supply a current less than zero signal current to said first inlet and said second current source being connected to supply more than zero signal current to said second inlet; and means responsive to reduction of input current to said first inlet to a value below that supplied by said first source to provide one signal and means responsive to increase of input to said second inlet to a value above that supplied by said second course to provide a second signal.

Claim 27

The invention defined in claim 20 which further comprises a set/reset flip-flop and means for applying said signals to a respectively associated one of the set and reset terminals of said flip-flop.

Claim 28

In combination: means for receiving bursts of radio frequency energy; detecting means for detecting the time, and providing a first signal when a burst first reaches a given amplitude; means for detecting the time, and providing a second signal, when the amplitude of a burst first falls to a given amplitude; said detecting means comprising a ring demodulator having first and second current inlet ports the inlet currents of which have a given ratio at zero input signal and the first of which decreases, and the second of which increases, with increasing input signal; first and second current sources connected to supply current in a constant ratio of currents; the first current source being connected to supply a current less than zero signal current to said first inlet port and said second current source being connected to supply more than zero signal current to said second port; and means responsive to reduction of input current to said first port to a value below that supplied by said first source to provide one signal and means responsive to increase of input to said second port to a value above that supplied by said second course to provide a second signal.

Claim 29

In combination: means for receiving bursts of radio frequency energy; detecting means for detecting the time, and providing a first signal when a burst first reaches a given amplitude; means for detecting the time, and providing a second signal, when the amplitude of a burst first falls to a given amplitude; said detecting means comprising a ring demodulator having first and second current inlet ports the inlet currents of which have a given ratio at zero input signal and the first of which decreases, and the second of which increases, with increasing input signal; first and second current sources connected to supply current in a constant ratio of currents; the first current source being connected to supply a current less than zero signal current to said first inlet port and said second current source being connected to supply more than zero signal current to said second port; and means responsive to reduction of input current to said first port to a value below that supplied by said first source to provide one signal and means responsive to increase of input to said second port to a value above that supplied by said second course to provide a second signal.

Claim 30

A demodulator of pulses whose leading and trailing edge have been formed at a time, relative to a reference time, that represents some intelligence, said demodulator comprising: (a) means for forming a rising signal and a falling signal at a time corresponding to the leading edge and the trailing edge of a pulse to be demodulated; (b) first and second pulse forming devices, one responsive to said rising signal rising to a given level to form a first pulse and the other responsive to said falling signal falling to a given level to form a second pulse; and (c) means for comparing the time of occurrence of said first and second pulses with said reference time.

Claim 31

A demodulator of pulses whose leading and trailing edge have been formed at a time, relative to a reference time, that represents some intelligence, said demodulator comprising: (a) means for forming a rising signal and a falling signal at a time corresponding to the leading edge and the trailing edge of a pulse to be demodulated; (b) first and second pulse forming devices, one responsive to said rising signal rising to a given level to form a first pulse and the other responsive to said falling signal falling to a given level to form a second pulse; and (c) means for comparing the time of occurrence of said first and second pulses with said reference time.

Claim 34

The method defined in claim 24 which includes the further step of receiving the pulses transmitted from the second station at said first station and there decoding them by determining the time variation in the occurrence of both edges of said pulses from said second station relative to the time of occurrence of said one edge of the pulses generated at said first station.

Claim 35

The invention defined in claim 25 which comprises the further steps of: causing said other edge of the pulses generated by said second station to be modulated according to an identity code; and causing said first station to demodulate said identity code, compare said code with its identity and generate and transmit its pulses only if the code matches its identity.

Claim 36

The invention defined in claim 25 which comprises the further step of causing one edge of the pulses generated and transmitted by said second station to be modulated in accordance with the identity of said second station; and causing said first station to cease generating and transmitting pulses when it ceases to receive pulses modulated in accordance with the identity of said second station.