USB - кабель для аудио
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oleksa
Ветеран
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Откуда: Киев
Сообщений: 1 033
Репутация: 101
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RE: USB - кабель для аудио / 14-09-2015 14:18
(11-09-2015 16:12)Тибетский Ламер писал(а): norrest, Юра, Изохронные передачи (Isochronous Transfers)
И еще вот:
"Isochronous transfers are used to transfer data in real-time between host and device. When an isochronous endpoint is set up by the host, the host allocates a specific amount of bandwidth to the isochronous endpoint, and it regularly performs an IN- or OUT-transfer on that endpoint. For example, the host may OUT 1 KByte of data every 125 us to the device. Since a fixed and limited amount of bandwidth has been allocated, there is no time to resend data if anything goes wrong. The data has a CRC as normal, but if the receiving side detects an error there is no resend mechanism."
И еще вот это:
"When transmitting digital audio, latency is introduced. In the case of High Speed USB this latency is 250 us. A packet of data is transferred once in every 125 us window, but given that it may be sent anytime in this window a 250 us buffer is required. On top of this 250 us delay, extra delay may be incurred in the O/S driver, and in the CODEC. Note that Full Speed USB has a much higher intrinsic latency of 2 ms, as data is only sent once in every 1 ms window."
(Отредактировал 14-09-2015 в 14:33 oleksa.)
"He thought he could actually hear ... that sort of illusion is what this hobby is all about" :)
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RE: USB - кабель для аудио - oleksa - 14-09-2015 14:18
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