Modulation of an RF transmit signal
First Claim
1. A circuit operative to modulate oscillation frequency of a transmit signal, the circuit comprising:
- a control block adapted to dynamically modulate a generated signal;
a filter adapted to modify a biasing voltage applied to a first terminal of a transistor in response to variations in the generated signal to generate a biasing signal; and
a pulse generator adapted to generate a pulse signal in response to detection of a transition of an oscillating signal, said transistor adapted to generate a radio frequency signal burst at a harmonic of the frequency of the generated pulse in response to receipt of a low-to-high or high-to-low transition of the generated pulse signal wherein voltage of the biasing signal selects the harmonic of the frequency of the pulse signal.
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Accused Products
Abstract
To modulate the frequency of a signal to be transmitted, the biasing voltage applied to a terminal of a transistor is dynamically modulated. To achieve this, the pulse width or a pulse amplitude of a control signal is modulated. Alternatively, a multi-bit control signal may be used to perform the modulation. The frequency of the transmitted signal is optionally modulated by varying the temperature of a oscillator. To vary this temperature, the current flowing through one or more resistive elements positioned in proximity of the oscillator is varied in response to the pulse width or amplitude of a second control signal. The temperature may also be changed by varying a multi-bit control signal. As the level of this current flow varies, the amount of heat emitted by the resistors vary, thereby changing the temperature of the oscillator which has a non-zero temperature coefficient.
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Citations
32 Claims
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1. A circuit operative to modulate oscillation frequency of a transmit signal, the circuit comprising:
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a control block adapted to dynamically modulate a generated signal; a filter adapted to modify a biasing voltage applied to a first terminal of a transistor in response to variations in the generated signal to generate a biasing signal; and a pulse generator adapted to generate a pulse signal in response to detection of a transition of an oscillating signal, said transistor adapted to generate a radio frequency signal burst at a harmonic of the frequency of the generated pulse in response to receipt of a low-to-high or high-to-low transition of the generated pulse signal wherein voltage of the biasing signal selects the harmonic of the frequency of the pulse signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A circuit operative to modulate oscillation frequency of a transmit signal, the circuit comprising:
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a control block adapted to dynamically modulate a generated signal; a filter adapted to modify a biasing voltage applied to a first terminal of a transistor in response to variations in the generated signal; a pulse generator adapted to generate a pulse signal in response to detection of a transition of an oscillating signal;
said transistor adapted to generate a radio frequency signal in response to receipt of a low-to-high or high-to-low transition of the generated pulse;an RC filter adapted to filter out high frequency components of the modulated signal; an amplifier adapted to generate the biasing signal in response to receipt of the filtered modulated signal at its positive input terminal, wherein a negative input terminal of the amplifier is coupled to an output terminal of the amplifier; and an oscillator adapted to generate the oscillating signal, wherein the generated signal is modulated by varying a value of a register disposed in the control block, wherein said control block is a commercially available microcontroller, and wherein a gate terminal of said transmit transistor is coupled to the ground potential. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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11. A method of modulating an oscillation frequency of a transmit signal, the method comprising:
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modulating a generated signal dynamically; varying a biasing signal in response to modulation of the generated signal; applying the biasing signal to a first terminal of a transmit transistor; generating a pulse in response to detection of a transition of a clock signal; applying the generated pulse to a second terminal of the transmit transistor to generate a radio frequency burst at a harmonic of the frequency of the generated pulse in response to a low-to-high or high-to-low transition of the generated pulse, wherein voltage of the biasing signal selects the harmonic of the frequency of the generated pulse. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method of modulating an oscillation frequency of a transmit signal, the method comprising:
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modulating a generated signal dynamically; varying a biasing signal in response to modulation of the generated signal; applying the biasing signal to a first terminal of a transmit transistor; generating a pulse in response to detection of a transition of a clock signal; and applying the generated pulse to a second terminal of the transmit transistor; filtering out high frequency components of the modulated signal; amplifying the filtered out modulated signal to generate the biasing signal; varying a register value for modulate the generated signal; and coupling a gate terminal of said transmit transistor to the ground potential. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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Specification