Method and device for optically transmitting data
First Claim
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1. A method for optically transmitting data using a pulse-width-modulated light source, the method comprising:
- specifying a pulse duty factor of a pulse width modulation to set the brightness of the light source as a ratio between a blanking time of the light source and a period of a pulse width modulation cycle, wherein a difference between the period and the blanking time corresponds to a bright-up time of the light source within one pulse width modulation cycle, anddividing the bright-up time of the pulse width modulation cycle into a plurality of partial bright-up times separated by at least one blanking to transmit a data symbol,wherein each blanking has a selected start time and time period,wherein the data symbol transmitted during the pulse width modulation cycle is defined as a function of the respective start times of all of the blankings within that pulse width modulation cycle,wherein the sum of the partial bright-up times within the pulse width modulation cycle essentially corresponds to the bright-up time according to the specified pulse duty factor; and
providing training sequences at least at the start of a data transmission.
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Abstract
In a method for optically transmitting data by means of a pulse-width-modulated light source (LED), a pulse duty factor (N) of a pulse width modulation is specified to set the brightness of the light source (LED). A bright time (T) is divided into at least a first and second partial bright time using at least one blanking so that the data (DATA) to be transmitted are encoded by the start and time length of the at least one blanking. The sum of the partial bright times within the pulse width modulation cycle substantially corresponds to the bright time according to the specified pulse duty factor.
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Citations
22 Claims
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1. A method for optically transmitting data using a pulse-width-modulated light source, the method comprising:
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specifying a pulse duty factor of a pulse width modulation to set the brightness of the light source as a ratio between a blanking time of the light source and a period of a pulse width modulation cycle, wherein a difference between the period and the blanking time corresponds to a bright-up time of the light source within one pulse width modulation cycle, and dividing the bright-up time of the pulse width modulation cycle into a plurality of partial bright-up times separated by at least one blanking to transmit a data symbol, wherein each blanking has a selected start time and time period, wherein the data symbol transmitted during the pulse width modulation cycle is defined as a function of the respective start times of all of the blankings within that pulse width modulation cycle, wherein the sum of the partial bright-up times within the pulse width modulation cycle essentially corresponds to the bright-up time according to the specified pulse duty factor; and providing training sequences at least at the start of a data transmission. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A device for optically transmitting data comprising:
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a pulse-width-modulated light source; and a data modulation module for receiving data to be transmitted and a settable pulse duty factor of a pulse width modulation as a ratio between a blanking time of the light source and a period of a pulse width modulation cycle, wherein a difference between the period and a blanking time corresponds to a bright-up time of the light source within one pulse width modulation cycle; wherein, the data modulation module is configured to divide the bright-up time into a plurality of partial bright-up times separated by at least one blanking to transmit a data symbol, wherein each blanking has a selected start time and time period, wherein the data symbol transmitted during the pulse width modulation cycle is defined as a function of the respective start times of all of the blankings within that pulse width modulation cycle, wherein the sum of the partial bright-up times within the pulse width modulation cycle essentially corresponds to the bright-up time according to the specified pulse duty factor; and wherein the pulse-width-modulated light source provides training sequences at least at the start of a data transmission. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification