Digital accessory interface calibration
First Claim
1. A method of compensating for a round-trip transmission delay in an audio system comprising:
- a portable communications device;
an audio accessory; and
a cable, suitable for connecting the portable communications device and the audio accessory, having at least one wire and being detachable from at least one of the portable communications device and the audio accessory,the method comprising;
at first times, transmitting on the at least one wire, from said device to said accessory, a first synchronisation data pattern, wherein said first synchronisation data pattern comprises first signal level transitions on the at least one wire, synchronised to a master transmission clock;
at second times, transmitting, on the at least one wire, from said accessory to said device, a second synchronisation data pattern, wherein said second synchronisation data pattern comprises second signal level transitions at timings that are set based on a delay value stored in said accessory;
in said device, determining, relative to the master transmission clock, timings of said second signal level transitions as received at said device;
transmitting, from said device to said accessory, timing delay control data based on said determination;
in said accessory, receiving said timing delay control data; and
updating said stored delay value based on said timing delay control data.
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Accused Products
Abstract
A method of compensating for a round-trip transmission delay in an audio system comprising: a portable communications device; an audio accessory; and a cable, suitable for connecting the portable communications device and the audio accessory, having at least one wire and being detachable from at least one of the portable communications device and the audio accessory. At first times, a first synchronization data pattern is transmitted on the at least one wire from said device to said accessory, wherein said first synchronization data pattern comprises first signal level transitions on the at least one wire, synchronized to a master transmission clock. At second times, a second synchronization data pattern is transmitted on the at least one wire from said accessory to said device, wherein said second synchronization data pattern comprises second signal level transitions at timings that are set based on a delay value stored in said accessory. In the device, timings of said second signal level transitions as received at said device are determined relative to the master transmission clock, and timing delay control data based on said determination is transmitted from the device to the accessory. In the accessory, the timing delay control data is received, and the stored delay value is updated based on the timing delay control data.
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Citations
33 Claims
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1. A method of compensating for a round-trip transmission delay in an audio system comprising:
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a portable communications device; an audio accessory; and a cable, suitable for connecting the portable communications device and the audio accessory, having at least one wire and being detachable from at least one of the portable communications device and the audio accessory, the method comprising; at first times, transmitting on the at least one wire, from said device to said accessory, a first synchronisation data pattern, wherein said first synchronisation data pattern comprises first signal level transitions on the at least one wire, synchronised to a master transmission clock; at second times, transmitting, on the at least one wire, from said accessory to said device, a second synchronisation data pattern, wherein said second synchronisation data pattern comprises second signal level transitions at timings that are set based on a delay value stored in said accessory; in said device, determining, relative to the master transmission clock, timings of said second signal level transitions as received at said device; transmitting, from said device to said accessory, timing delay control data based on said determination; in said accessory, receiving said timing delay control data; and updating said stored delay value based on said timing delay control data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of compensating for a round-trip transmission delay in an audio system comprising:
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a portable communications device; an audio accessory; and a cable, suitable for connecting the portable communications device and the audio accessory, having at least one wire and being detachable from at least one of the portable communications device and the audio accessory, the method comprising, in the portable communications device; at first times, transmitting on the at least one wire first synchronisation data pattern, wherein said first synchronisation data pattern comprises first signal level transitions on the at least one wire, synchronised to a master transmission clock; at second times, receiving from said accessory a second synchronisation data pattern, wherein said second synchronisation data pattern comprises second signal level transitions; determining, relative to the master transmission clock, timings of said second signal level transitions as received at said device; and transmitting to said accessory timing delay control data based on said determination. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification