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projects:hifi:retrofitting_coaxial_spdif_out

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projects:hifi:retrofitting_coaxial_spdif_out [2023/04/08 01:39] adminprojects:hifi:retrofitting_coaxial_spdif_out [2024/10/24 12:41] (current) admin
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 ====== Retrofitting coaxial spdif out ====== ====== Retrofitting coaxial spdif out ======
-This page describes how to add to a device with has already an optical spdif output a coaxial spdif output as well.+This page describes how to add to a device which has already an optical spdif output a coaxial spdif output.
  
 The modification described on this page is to add a coaxial spdif output to a Sony MDS-JE520 MiniDisc deck. Although it contains both an optical and coaxial spdif input, it only contains an optical spdif output. The lack of a coaxial spdif output is inconvenient and this modification mitigates that. The modification described on this page is to add a coaxial spdif output to a Sony MDS-JE520 MiniDisc deck. Although it contains both an optical and coaxial spdif input, it only contains an optical spdif output. The lack of a coaxial spdif output is inconvenient and this modification mitigates that.
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 |  //Schematic of spdif coax interface//  | |  //Schematic of spdif coax interface//  |
  
-The schematic is in essence an impedance matched voltage divider. Since the transformer has a 1:1 ratio, the signal is AC only and the three inverter driver outputs U1A, U1B and U1C are all identical, the schematic can be simplified for calculation. +The schematic is in essence an impedance matched voltage divider. Since the transformer ([[https://www.lundahltransformers.com/wp-content/uploads/datasheets/1572_1573_1589.pdf|Lundahl 1572]]) has a 1:1 ratio, the signal is AC only and the three inverter driver outputs U1A, U1B and U1C are all identical, the schematic can be simplified for calculation. 
  
 S/PDIF signals are defined in IEC 60958-3 (2003)((Digital audio interface, Part 3)). The output shall have a substantial resistive impedance of $(75\ \pm\ 15) (\Omega)$ when measured at frequencies from 0.1 MHz to 128 times the maximum frame rate, which equals to about 5.6 MHz for a sample rate of 44.1 kHz. The signal amplitude shall be $(0.5\ \pm\ 0.1 ) {\text V}$ peak-to-peak, when measured across a $(75\ \pm\ 0.75) (\Omega)$ resistor connected to the output terminals, without any interconnecting cable present. S/PDIF signals are defined in IEC 60958-3 (2003)((Digital audio interface, Part 3)). The output shall have a substantial resistive impedance of $(75\ \pm\ 15) (\Omega)$ when measured at frequencies from 0.1 MHz to 128 times the maximum frame rate, which equals to about 5.6 MHz for a sample rate of 44.1 kHz. The signal amplitude shall be $(0.5\ \pm\ 0.1 ) {\text V}$ peak-to-peak, when measured across a $(75\ \pm\ 0.75) (\Omega)$ resistor connected to the output terminals, without any interconnecting cable present.
projects/hifi/retrofitting_coaxial_spdif_out.1680910773.txt.gz · Last modified: 2023/04/08 01:39 by admin