Active transmitter ringdown for switching power amplifier
First Claim
1. A method for controlling signal decay of an electro-magnetic transmission from a transmitter, said method comprising:
- measuring an amount of current induced into the transmitter by a decaying field remaining after the electro-magnetic transmission; and
using the current measurement to control a decay rate of the decaying field.
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Accused Products
Abstract
A method for controlling signal decay of a transmitted signal within a transmitter is described. The method includes measuring an amount of current induced back into the transmitter by the decaying signal, and using the current measurement to control the decay of the signal after the signal is transmitted from the load. A transmitter for an electronic article surveillance (EAS) system is also described which includes a current sensing circuit configured to at least sense an amount of current induced back into the transmitter by the load after transmission of the signal, and a transmitter control circuit configured to utilize the sensed current to determine an amount and a polarity of current to be applied to the load to reduce the induced current to a desired value.
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Citations
21 Claims
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1. A method for controlling signal decay of an electro-magnetic transmission from a transmitter, said method comprising:
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measuring an amount of current induced into the transmitter by a decaying field remaining after the electro-magnetic transmission; and using the current measurement to control a decay rate of the decaying field. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A transmitter for an electronic article surveillance (EAS) system, said transmitter configured to output a transmission signal to an external load, said transmitter comprising:
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a current sensing circuit configured to at least sense an amount of current induced back into said transmitter by the load after transmission of the signal; and a transmitter control circuit configured to utilize the sensed current to determine an amount and a polarity of current to be applied to the load to reduce the induced current to a desired value. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. An electronic article surveillance (EAS) system comprising:
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a receiver configured to receive signals generated by EAS tags; and a transmitter configured to apply a signal to a load and further configured to transmit a signal at a resonant frequency of the EAS tag, said transmitter further configured to sense both an amount of current applied to the load during transmission periods and an amount of current induced by the load back into said transmitter during non-transmission periods, said transmitter configured to utilize the sensed currents to control an amount and a polarity of current applied to the load during both transmission periods and non-transmission periods. - View Dependent Claims (18, 19, 20, 21)
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Specification