Antenna drive apparatus
First Claim
1. An antenna drive apparatus configured to apply an antenna drive voltage to an antenna from an H-bridge circuit including four switching elements to drive the antenna, comprising:
- a switching mechanism configured to switch between a full-bridge state in which a differential voltage between a pulse voltage and a reverse pulse voltage reversed from the pulse voltage is applied to the antenna as the antenna drive voltage by the H-bridge circuit, and a half-bridge state in which the pulse voltage or the reverse pulse voltage is applied to the antenna as the antenna drive voltage by the H-bridge circuit; and
a control mechanism configured to control the switching mechanism so that the frequency of the full-bridge state per unit time during an initial period of driving of the antenna in a transmission period for transmitting a transmission signal by the antenna becomes higher than that during the subsequent period subsequent to the initial period in the transmission period.
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Accused Products
Abstract
An antenna drive apparatus applying an antenna drive voltage to an antenna from an H-bridge circuit including four switching elements to drive the antenna, includes: a switching mechanism to switch between a full-bridge state in which a differential voltage between a pulse voltage and a reverse pulse voltage reversed from the pulse voltage is applied to the antenna as the antenna drive voltage, and a half-bridge state in which the pulse voltage or the reverse pulse voltage is applied to the antenna as the antenna drive voltage; and a control mechanism to control the switching mechanism so that the frequency of the full-bridge state per unit time during an initial period of driving of the antenna in a transmission period for transmitting a transmission signal by the antenna becomes higher than that during the subsequent period in the transmission period.
11 Citations
8 Claims
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1. An antenna drive apparatus configured to apply an antenna drive voltage to an antenna from an H-bridge circuit including four switching elements to drive the antenna, comprising:
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a switching mechanism configured to switch between a full-bridge state in which a differential voltage between a pulse voltage and a reverse pulse voltage reversed from the pulse voltage is applied to the antenna as the antenna drive voltage by the H-bridge circuit, and a half-bridge state in which the pulse voltage or the reverse pulse voltage is applied to the antenna as the antenna drive voltage by the H-bridge circuit; and a control mechanism configured to control the switching mechanism so that the frequency of the full-bridge state per unit time during an initial period of driving of the antenna in a transmission period for transmitting a transmission signal by the antenna becomes higher than that during the subsequent period subsequent to the initial period in the transmission period. - View Dependent Claims (2, 3, 4)
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5. An antenna drive apparatus configured to drive an antenna by controlling a duty ratio of a pulsed drive signal which applies an antenna drive voltage to the antenna, comprising:
a control mechanism for controlling the duty ratio of the drive signal so that an average value of the duty ratio during a predetermined initial period of driving of the antenna in a transmission period for transmitting a transmission signal by the antenna is closer to 50% than a predetermined duty ratio set during the subsequent period subsequent to the predetermined initial period in the transmission period. - View Dependent Claims (6, 7, 8)
Specification