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Fast and Efficient PSK Modulation With Resonant Antennas

IP.com Disclosure Number: IPCOM000247912D
Publication Date: 2016-Oct-11
Document File: 4 page(s) / 146K

Publishing Venue

The IP.com Prior Art Database

Related People

Microchip Technology Inc: OWNER

Abstract

The disclosed techniques hold the phase (state) of a resonant antenna for a specified time and then release the antenna after that specified time. The antenna continues to operate after the specified time at the state where it was stopped. Any phase shift can be realized and no DC current or voltage source is needed. PSK can be modulated by conserving the capacitor voltage for a certain time and release the resonating circuit after that time. After releasing the antenna, the antenna will continue to oscillate at the state it was in at the beginning of the specified time. As the antenna energy is conserved during modulation there is much less energy loss making the approach much more energy efficient than conventional systems. Because the amplitude/phase can be stored in the ASK/PSK modulation system for a specified time, and the antenna can continue to resonate at the state it was stopped after the specified time, the data rate is higher than with conventional systems.

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Fast and Efficient PSK Modulation With Resonant Antennas

1.1    Keywords

Resonant antenna, phase shift key modulation, PSK modulation, amplitude shift key modulation, ASK modulation, wireless transponder, base station, immobilizer, passive entry, passive start 

1.2    Summary Description

A resonant antenna active feedback transmission system can be used to increase the operating distance between two nodes of a passive transponder system.  In base stations for automotive applications that use immobilizers, passive entry and passive start technologies, resonant antennas with high Q-factors can be used to reduce the power needed for transmission.

The techniques disclosed herein are intended to save power and increase data rates of amplitude shift key (ASK) modulation or phase shift key (PSK) modulation transmission systems.  Increasing the data rate reduces the response time of the system and reduces power consumption due to lower transmission time.  The proposed technique also conserves power by storing power within the resonant antenna during modulation.

1.3    Technical field

The disclosed techniques can be used for ASK or PSK modulation of a base station resonant antenna in automotive applications that use an immobilizer or passive entry or passive start system.

1.4    Problem

In prior art resonant antenna systems, it takes time to reach a new stable amplitude/phase condition after switching the transmitted signal ON/OFF in ASK modulation systems or after a phase shift in PSK modulation systems.  In both cases, the energy stored in the antenna is lost.  For active transponder feedback transmission, the requirement is high energy efficiency and high data rates to keep system response time low.

1.5    Summary

The disclosed techniques hold the phase (state) of the antenna for a specified time and then release the antenna after that specified time.  The antenna continues to operate after the specified time at the state where it was stopped.  Any phase shift can be realized and no DC current or voltage source is needed.   PSK can be modulated by conserving the capacitor voltage for a certain time and release the resonating circuit after that time.  After releasing the antenna, the antenna will continue to oscillate at the state it was in at the beginning of the specified time.

1.6    Advantages:

As the antenna energy is conserved during modulation there is much less energy loss making the approach much more energy efficient than conventional systems.  Because the amplitude/phase can be stored in the ASK/PSK modulation system for a specified time, and the antenna can continue to resonate at the state it was stopped after the specified time, the data rate is higher than with conventional systems.

1.7    Detailed Description:

The principle operation of the invention is explained in more detail below with reference to FIG. 1.

Figure 1

Figure 1 illustrates an example binary phase shift key (BPSK) modulation of a resonant circuit including an inductor L and a c...