Apparatus and method for frequency shift keying
OwnerOve Kris Gashusinventor
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Abstract
A transmitter for generating and transmitting frequency shift keying signals. The transmitter comprises a resonant circuit, a capacitor, a switch for coupling and decoupling the capacitor to the resonant circuit, a sensor and a controller. The controller includes an input for receiving a data signal. The controller actuates the switch to selectively couple the capacitor to the resonant circuit based on the state of the data signal. The sensor determines when the energy level in the capacitor is substantially zero and the controller synchronizes actuation of the switch with the substantially zero energy state of the capacitor. The transmitter also includes a circuit for efficiently supplying power to the resonant circuit in form the power pulses.
Claims12
A frequency shift keying generator comprising:
- (a) a resonant circuit;
- (b) a reactive element;
- (c) a switch for coupling and decoupling said reactive element to and from said resonant circuit, said resonant circuit oscillating at a first frequency when said reactive element is coupled and said resonant circuit oscillating at a second frequency when said reactive element is uncoupled;
- (d) a power supply having an output port coupled to said resonant circuit, said power supply including means responsive to a control signal for enabling said output port for energizing said resonant circuit;
- (e) a detector coupled to said resonant circuit for detecting an energy level for said reactive element and producing an output signal indicative of said energy level;
- and
- (f) a controller for controlling said switch, said controller including an output port for actuating said switch and an input port coupled to said detector for receiving said energy level output signal, said controller also having a data input for receiving a data signal and means for selectively actuating said switch to shift the oscillation of said resonant circuit between said first and second frequencies in response to a change of state in the data signal, and said controller including means responsive to said energy level for synchronizing the actuation of said switch with the energy level in said reactive element.
A frequency shift keying generator comprising:
- (a) a resonant circuit;
- (b) a reactive element;
- (c) a switch for coupling and decoupling said reactive element to and from said resonant circuit, said resonant circuit oscillating at a first frequency when said reactive element is coupled and said resonant circuit oscillating at a second frequency when said reactive element is uncoupled;
- (d) a power supply having an output port coupled to said resonant circuit, said power supply including means responsive to a control signal for enabling said output port for energizing said resonant circuit;
- (e) a sensor coupled to said resonant circuit, said sensor including means for sensing current flow in said resonant circuit and means for generating an output signal indicative of the current flow;
- (f) a controller for controlling said switch, said controller including an output port for actuating said switch and a data input for receiving a data signal and means for selectively actuating said switch to shift the oscillation of said resonant circuit between said first and second frequencies in response to a change of state in the data signal, and said controller including means responsive to said current flow signal for generating said control signal for enabling said output port and coupling said power supply to said resonant circuit for a predetermined duration when the current flow is substantially zero, so that energy is injected into said resonant circuit when said output port is enabled.
A method for producing frequency shift keying in an oscillating carrier signal, the oscillating carrier signal being generated by a resonant circuit having a modulating capacitor and a switch for selectively coupling and decoupling the capacitor to the resonant circuit, said method comprising the steps of:
- (a) generating the oscillating carrier signal at a given frequency;
- (b) receiving a binary data signal comprising a sequence of binary states;
- (c) monitoring the energy level in the modulating capacitor;
- (d) introducing a shift in the frequency of said oscillating carrier signal when there is a change in the binary state of the data signal;
- (e) wherein said step of introducing a frequency shift comprises selectively coupling the modulating capacitor to the resonant circuit and wherein said step, of coupling is synchronized to the monitored energy level in the modulating capacitor.
Dependencies are inferred from the claim text.