EP0800267A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Apparatus for envelope shaping of burst signals in a transmitter

Assignee: Panasonic Holdings Corp

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Filing: 1997-03-21

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Granted: —

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Expires: 2017-03-21

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Abstract

Abstract A transmission apparatus using the modulation system in which an envelope is reduced to zero at a moment on the way of transmission includes a mapping circuit (1) for mapping a transmission signal in the signal point arrangement, D/A converters (2, 3) for converting signals for I and Q channels obtained by the mapping circuit into respective analog signals, switches (4, 5) for turning on and off the respective converted analog signals in accordance with a transmission on/off control signal, and band restriction filters (6, 7) for band-restricting the on-and-off controlled analog signals. Variation of the envelope is increased on the way of transmission as compared with just after the beginning of transmission and accordingly by suppressing leakage power between adjacent channels during transmission by the filters (6, 7), the ramp process can be performed practically in accordance with on and off control of transmission by the switches (4, 5).

Inventors

👤 Katsuhiko Hiramatsu

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-10-26 19:02

CPC Classifications

H; H04; H04B; H04B14/00; H04B14/02; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3036; H03G3/3042; H03G3/3047; H04L; H04L27/00; H04L27/18; H04L27/20; H04L27/2032; H04L27/2053; H04L27/206; H04L27/2067; H04L27/2071

Claims Analysis

Total Claims: 3

Claim 1

Independent Claim 169 words

A transmission apparatus for modulating a carrier signal by transmission data and transmitting the modulated carrier signal having an envelope an amplitude of which is reduced to substantially zero in accordance with predetermined change of the transmission data, said apparatus comprising: a mapping circuit (1) for mapping the transmission data into one of predetermined signal points in the orthogonal coordinates to produce a data signal of a first channel corresponding to one coordinate axis in the orthogonal coordinates and a data signal of a second channel corresponding to the other coordinate axis; digital-to-analog converters (2, 3) for converting the data signals of the first and second channels produced by said mapping circuit (1) into respective analog signals; switch means (4, 5) for turning on and off the respective analog signals converted by said digital-to-analog converters (2, 3) in accordance with a control signal which controls on and off of transmission of said transmission apparatus; and filter means (6, 7) for band-restricting output signals of said switch means (4, 5).

Claim 2

Dependent Claim 205 words

A transmission apparatus for modulating a carrier signal by transmission data and transmitting the modulated carrier signal having an envelope an amplitude of which is reduced to substantially zero in accordance with predetermined change of the transmission data, said apparatus comprising: a mapping circuit (21) for mapping the transmission data into one of predetermined signal points in the orthogonal coordinates to produce a data signal of a first channel corresponding to one coordinate axis in the orthogonal coordinates and a data signal of a second channel corresponding to the other coordinate axis; a ramp circuit (22) for receiving the data signals of the first and second channels produced by said mapping circuit (21) to output selected one of the data signal of the first channel and a predetermined potential and output selected one of the data signal of the second channel and the predetermined potential in accordance with a control signal which controls on and off of transmission of said transmission apparatus; digital-to-analog converters (23, 24) for converting the data signals of the first and second channels produced by said ramp circuit (22) into respective analog signals; and filter means (25, 26) for band-restricting the respective analog signals converted by said digital-to-analog converters (23, 24).

Claim 3

Dependent Claim 33 words

A transmission apparatus according to claim 2, wherein: said ramp circuit (22) outputs 2-bit digital data and said digital-to-analog converters (23, 24) receives the 2-bit digital data to output analog signal corresponding thereto.

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