Abstract: Coaxial helix antennas in accordance with embodiments of the invention are disclosed. In one embodiment, a coaxial helix antenna includes an inner element having an inner element radius and an inner element length and an outer element having an outer element radius and an outer element length, wherein the outer element radius is greater than the inner element radius, wherein the inner element is driven by a first conductor, wherein the outer element is driven by a second conductor, and wherein the outer element is disposed outside of the inner element such that a portion of the inner element extends beyond the outer element and includes an inner radiating element.

Abstract: Coaxial helix antennas in accordance with embodiments of the invention are disclosed. In one embodiment, a coaxial helix antenna includes an inner element having an inner element radius and an inner element length and an outer element having an outer element radius and an outer element length, wherein the outer element radius is greater than the inner element radius, wherein the inner element is driven by a first conductor, wherein the outer element is driven by a second conductor, and wherein the outer element is disposed outside of the inner element such that a portion of the inner element extends beyond the outer element and includes an inner radiating element.

Abstract: A battery protection system with a voltage sensing circuit for sensing the voltage of a battery and disconnecting all loads from the battery, including the voltage sensing circuit itself, when the voltage of the battery drops below a preset limit or when a battery charger is connected to the battery. The battery protection system reconnects the voltage sensing circuit upon disconnection of the battery charger.

Abstract: Coaxial helix antennas in accordance with embodiments of the invention are disclosed. In one embodiment, a coaxial helix antenna includes an inner element having an inner element radius and an inner element length and an outer element having an outer element radius and an outer element length, wherein the outer element radius is greater than the inner element radius, wherein the inner element is driven by a first conductor, wherein the outer element is driven by a second conductor, and wherein the outer element is disposed outside of the inner element such that a portion of the inner element extends beyond the outer element and includes an inner radiating element.

Abstract: A battery protection system with a voltage sensing circuit for sensing the voltage of a battery and disconnecting all loads from the battery, including the voltage sensing circuit itself, when the voltage of the battery drops below a preset limit or when a battery charger is connected to the battery. The battery protection system reconnects the voltage sensing circuit upon disconnection of the battery charger.

Abstract: Coaxial helix antennas in accordance with embodiments of the invention are disclosed. In one embodiment, a coaxial helix antenna includes an inner element having an inner element radius and an inner element length and an outer element having an outer element radius and an outer element length, wherein the outer element radius is greater than the inner element radius, wherein the inner element is driven by a first conductor, wherein the outer element is driven by a second conductor, and wherein the outer element is disposed outside of the inner element such that a portion of the inner element extends beyond the outer element and includes an inner radiating element.

Abstract: Single stage ramped power amplifiers in accordance with embodiments of the invention are disclosed. In one embodiment, a single stage ramped power amplifier includes a RF transceiver, a ramp voltage, a power supply, and an output circuit, wherein the ramp voltage is coupled to a resistor that is coupled to a first inductor, the power supply is coupled to a second inductor, the RF transceiver is coupled to the second inductor and a first capacitor, the first capacitor is coupled to a PIN diode, the PIN diode is coupled to the first inductor and a second capacitor, the second capacitor is coupled to a first transistor, the first transistor is coupled to a third capacitor, the third capacitor is coupled to a third inductor, the third inductor is coupled to a second transistor, and the second transistor is coupled to the output circuit.

Abstract: Single stage ramped power amplifiers in accordance with embodiments of the invention are disclosed. In one embodiment, a single stage ramped power amplifier includes a RF transceiver, a ramp voltage, a power supply, and an output circuit, wherein the ramp voltage is coupled to a resistor that is coupled to a first inductor, the power supply is coupled to a second inductor, the RF transceiver is coupled to the second inductor and a first capacitor, the first capacitor is coupled to a PIN diode, the PIN diode is coupled to the first inductor and a second capacitor, the second capacitor is coupled to a first transistor, the first transistor is coupled to a third capacitor, the third capacitor is coupled to a third inductor, the third inductor is coupled to a second transistor, and the second transistor is coupled to the output circuit.

Abstract: A wireless microphone with the remote transmitter using a duplicate of the radio frequency determining circuits of the radio receiver to insure that the remote transmitter frequency tracks the temperature drift of the radio receiver frequency, and also with a compressor to reduce the dynamic range of the sounds captured by the microphone. The superheterodyne radio receiver having small size and low current consumption by wiring the elements of the receiver in series rather than in parallel with the battery avoiding the use of switching regulators and also by using the same amplifier to amplify the antenna signal and the local oscillator signal and by adjusting the local oscillator current based on the strength of the received radio signal. The wires between the radio receiver and the speaker are part of the antenna for the radio receiver.

Abstract: A wireless microphone with the remote transmitter using a duplicate of the radio frequency determining circuits of the radio receiver to insure that the remote transmitter frequency tracks the temperature drift of the radio receiver frequency, and also with a compressor to reduce the dynamic range of the sounds captured by the microphone. The superheterodyne radio receiver having small size and low current consumption by wiring the elements of the receiver in series rather than in parallel with the battery avoiding the use of switching regulators and also by using the same amplifier to amplify the antenna signal and the local oscillator signal and by adjusting the local oscillator current based on the strength of the received radio signal. The wires between the radio receiver and the speaker are part of the antenna for the radio receiver.

Abstract: Coaxial helix antennas in accordance with embodiments of the invention are disclosed. In one embodiment, a coaxial helix antenna includes an inner element having an inner element radius and an inner element length and an outer element having an outer element radius and an outer element length, wherein the outer element radius is greater than the inner element radius, wherein the inner element is driven by a first conductor, wherein the outer element is driven by a second conductor, and wherein the outer element is disposed outside of the inner element such that a portion of the inner element extends beyond the outer element and includes an inner radiating element.

Abstract: A SAW resonator filter including a SAW resonator, and a first inductive reactance in parallel with the SAW resonator for shifting the null points below and above the center frequency for establishing substantially symmetrical attenuation about the center frequency.

Abstract: An improved fast settling bit slicing comparator circuit includes a comparator having a non-inverting and inverting input; the non-inverting input receiving an input signal; a filter circuit for receiving the input signal and being connected with the inverting input of the comparator; a positive feedback circuit interconnected between the output of the comparator and the non-inverting input of the comparator for introducing a predetermined hysteresis offset; the filter circuit including a filter resistance and filter capacitance having a reduced time constant sufficient to compensate for at least a portion of the hysteresis offset. Additionally, the positive feedback circuit may be interconnected with the inverting input of the comparator through the filter circuit for gradually reducing the effect of the hysteresis offset by reducing the differential voltage between the inverting and non-inverting inputs.

Abstract: A notched SAW image frequency rejection filter system includes a SAW filter having an input, an output and a ground output and an impedance matching network including a first matching inductance connected to the SAW filter output and a second matching inductance connected to the ground output of the SAW filter; the SAW filter having an inherent internal capacitance that produces a predetermined capacitive leakage current at the image frequency; an inherent internal inductance that produces an inductance leakage current at the image frequency; and a boosted inherent parasitic ground inductance at the ground output of the SAW filter for generating a voltage across the second matching inductance to produce a compensation current which is substantially opposite in phase and substantially matched in magnitude with the capacitive leakage current for reducing the capacitive leakage current and increasing the image frequency rejection.

Abstract: Dual table temperature compensation for a voltage controlled crystal oscillator is achieved by sensing the temperature of the voltage controlled crystal oscillator (VCXO), retrieving from a first table the frequency error with variations in the temperature sensed, retrieving from a second table the oscillator control voltage corresponding to the frequency error from the first table and applying the oscillator control voltage to the VCXO.

Abstract: Dual table temperature compensation for a voltage controlled crystal oscillator is achieved by sensing the temperature of the voltage controlled crystal oscillator (VCXO), retrieving from a first table the frequency error with variations in the temperature sensed, retrieving from a second table the oscillator control voltage corresponding to the frequency error from the first table and applying the oscillator control voltage to the VCXO.

Abstract: A fast start, low power oscillator system includes an oscillator circuit including an amplifier and a tank circuit, the amplifier including an operating resistance which sets the amplifier operating current and a speed-up circuit including a switching circuit for temporarily increasing the operating current to an elevated level at start-up and then returning it to the original operating current when the oscillator reaches its operating amplitude.

Abstract: An improved fast settling bit slicing comparator circuit includes a comparator having a non-inverting and inverting input; the non-inverting input receiving an input signal; a filter circuit for receiving the input signal and being connected with the inverting input of the comparator; a positive feedback circuit interconnected between the output of the comparator and the non-inverting input of the comparator for introducing a predetermined hysteresis offset; the filter circuit including a filter resistance and filter capacitance having a reduced time constant sufficient to compensate for at least a portion of the hysteresis offset. Additionally, the positive feedback circuit may be interconnected with the inverting input of the comparator through the filter circuit for gradually reducing the effect of the hysteresis offset by reducing the differential voltage between the inverting and non-inverting inputs.

Abstract: A notched SAW image frequency rejection filter system includes a SAW filter having an input, an output and a ground output and an impedance matching network including a first matching inductance connected to the SAW filter output and a second matching inductance connected to the ground output of the SAW filter; the SAW filter having an inherent internal capacitance that produces a predetermined capacitive leakage current at the image frequency; an inherent internal inductance that produces an inductance leakage current at the image frequency; and a boosted inherent parasitic ground inductance at the ground output of the SAW filter for generating a voltage across the second matching inductance to produce a compensation current which is substantially opposite in phase and substantially matched in magnitude with the capacitive leakage current for reducing the capacitive leakage current and increasing the image frequency rejection.

Abstract: A SAW resonator filter including a SAW resonator, and a first inductive reactance in parallel with the SAW resonator for shifting the null points below and above the center frequency for establishing substantially symmetrical attenuation about the center frequency.