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| author | version | line-number | content |
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53.1 | 1 | == Internal latency measurement of the ERMAK-TT transceiver == |
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1.2 | 2 | |
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53.1 | 3 | * Transmit mode (microphone input -> RF output): **45ms** |
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1.2 | 4 | |
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5.1 | 5 | |
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3.2 | 7 | [[image:1777980550259-754.png]] |
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53.1 | 10 | * Receive mode (RF modulator output -> headphone output): **52ms** |
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5.1 | 11 | |
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7.1 | 12 | |
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4.2 | 14 | [[image:1777980668036-257.png]] |
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5.1 | 15 | |
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7.2 | 16 | |
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53.1 | 17 | == Internal latency measurement of FLEX radio == |
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7.2 | 18 | |
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12.2 | 19 | * [[https:~~/~~/community.flexradio.com/discussion/8027536/signal-in-to-audio-out-rf-to-audio-latency>>https://community.flexradio.com/discussion/8027536/signal-in-to-audio-out-rf-to-audio-latency]] |
| 20 | * [[https:~~/~~/www.n1kdo.com/sdr-delay-measured/>>url:https://www.n1kdo.com/sdr-delay-measured/]] | ||
| 21 | * [[https:~~/~~/community.flexradio.com/discussion/6865953/>>url:https://community.flexradio.com/discussion/6865953/]] | ||
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7.2 | 22 | |
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12.2 | 25 | [[image:1778007502882-224.png]] |
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7.2 | 26 | |
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12.2 | 27 | [[image:RackMultipart20151208-21021-1jin1qg-scope_1000_inline.png||alt="image"]] [[image:RackMultipart20151208-13976-moh3cq-scope_800_inline.png||alt="image"]] [[image:RackMultipart20151208-7743-183a2a1-scope_400_inline.png||alt="image"]] |
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15.2 | 30 | [[image:1778007575902-770.png]] |
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12.2 | 31 | |
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23.1 | 34 | [[image:image.png]] [[image:https://us.v-cdn.net/6032377/uploads/OB7NPE9JDLNX/image.png||alt="image.png"]] |
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15.2 | 35 | |
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53.1 | 37 | Thanks to [[Mike-VA3MW>>url:https://community.flexradio.com/profile/Mike-VA3MW]] and [[W7NGA>>url:https://community.flexradio.com/profile/W7NGA]] |
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15.2 | 38 | |
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53.1 | 40 | == Total latency measurement of the ERMAK-TT transceiver + EAX (USB) == |
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19.2 | 41 | |
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53.1 | 42 | Measurements were performed on a Windows 11 PC Host + VAC by Eugene Muzychenko. The original VAC from ERMAK can also be used. They provide slightly lower latency due to optimized buffers. |
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19.2 | 43 | |
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53.1 | 44 | **Important note** - the original ERMAK VAC drivers are signed with a self-signed certificate. Therefore, driver signature verification must be disabled on the PC host. |
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19.2 | 45 | |
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53.1 | 46 | 1. [[EAX audio control - release history>>https://sdr-ermak.com/xwiki/bin/view/Main/ERMAK-TT/EAX%20aduio%20control%20utility%20releases/]] |
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20.2 | 47 | 1. [[EAX VAC Windows 10>>https://nx8619.your-storageshare.de/s/pdeEJr5mG4ix7PQ?dir=/EAX%20VAC]] |
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53.1 | 48 | 1. [[Installing and configuring EAX on WINDOWS>>https://sdr-ermak.com/xwiki/bin/view/Main/ERMAK/%D0%A0%D1%83%D0%BA%D0%BE%D0%B2%D0%BE%D0%B4%D1%81%D1%82%D0%B2%D0%BE%20%D0%BF%D0%BE%D0%BB%D1%8C%D0%B7%D0%BE%D0%B2%D0%B0%D1%82%D0%B5%D0%BB%D1%8F%20%D0%95%D0%A0%D0%9C%D0%90%D0%9A/EAX%20-%20%D1%83%D1%82%D0%B8%D0%BB%D0%B8%D1%82%D0%B0%20%D0%BE%D0%B1%D0%BC%D0%B5%D0%BD%D0%B0%20%D0%B0%D1%83%D0%B4%D0%B8%D0%BE%D0%BF%D0%BE%D1%82%D0%BE%D0%BA%D0%B0%D0%BC%D0%B8%20%D1%81%20PC/%D0%A3%D1%81%D1%82%D0%B0%D0%BD%D0%BE%D0%B2%D0%BA%D0%B0%20%D0%B8%20%D0%BD%D0%B0%D1%81%D1%82%D1%80%D0%BE%D0%B9%D0%BA%D0%B0%20EAX%20%D0%B2%20%D1%81%D1%80%D0%B5%D0%B4%D0%B5%20WINDOWS/]] |
| 49 | 1. [[Installing and configuring EAX on LINUX>>https://sdr-ermak.com/xwiki/bin/view/Main/ERMAK/%D0%A0%D1%83%D0%BA%D0%BE%D0%B2%D0%BE%D0%B4%D1%81%D1%82%D0%B2%D0%BE%20%D0%BF%D0%BE%D0%BB%D1%8C%D0%B7%D0%BE%D0%B2%D0%B0%D1%82%D0%B5%D0%BB%D1%8F%20%D0%95%D0%A0%D0%9C%D0%90%D0%9A/EAX%20-%20%D1%83%D1%82%D0%B8%D0%BB%D0%B8%D1%82%D0%B0%20%D0%BE%D0%B1%D0%BC%D0%B5%D0%BD%D0%B0%20%D0%B0%D1%83%D0%B4%D0%B8%D0%BE%D0%BF%D0%BE%D1%82%D0%BE%D0%BA%D0%B0%D0%BC%D0%B8%20%D1%81%20PC/%D0%A3%D1%81%D1%82%D0%B0%D0%BD%D0%BE%D0%B2%D0%BA%D0%B0%20%D0%B8%20%D0%BD%D0%B0%D1%81%D1%82%D1%80%D0%BE%D0%B9%D0%BA%D0%B0%20EAX%20%D0%B2%20%D1%81%D1%80%D0%B5%D0%B4%D0%B5%20LINUX/]] | ||
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19.9 | 50 | |
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53.1 | 53 | * Receive mode (RF modulator output -> EAX -> PC audio output): **197ms** |
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20.2 | 54 | |
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22.1 | 55 | |
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20.2 | 57 | [[image:1778050748939-595.png]] |
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21.2 | 58 | |
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53.1 | 60 | * Receive mode (RF modulator output -> USB audio -> PC audio output): **220ms** |
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21.2 | 61 | |
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22.1 | 62 | |
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21.2 | 64 | [[image:1778051095734-567.png]] |
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23.2 | 66 | |
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53.1 | 67 | == Total latency measurement of the ERMAK-TT transceiver + EAX (USB) and Flex radio in remote mode == |
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23.2 | 68 | |
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53.1 | 69 | **Measurement program** |
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47.1 | 70 | |
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53.1 | 71 | * **ERMAK-TT** — local connection to PC + EAX |
| 72 | * **FlexRadio** — remote connection (~~5000 km), RTT ~~100 ms, DAX v2, "long" filters. Propagation speed ≈ 3×10⁸ m/s → latency over 5000 km (one-way) ≈ 16.7 ms; network RTT 100 ms → one-way ≈ 50 ms; total ≈ **67-70 ms margin** | ||
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47.1 | 73 | |
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53.1 | 74 | **Measurement subject:** |
| 75 | Reception of one-second pulses at 4999 kHz | ||
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47.1 | 76 | |
| 77 | [[image:1778072528651-371.png]] | ||
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53.1 | 80 | * Red ERMAK-TT |
| 81 | * Blue - FLEX radio. "Fast" filters (51ms) | ||
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47.1 | 82 | |
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53.1 | 83 | Result: 104ms-70ms=**30ms**, ** ERMAK-TT provides lower latency** |
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47.1 | 84 | |
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50.2 | 85 | [[image:1778072986007-908.png]] |
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47.1 | 86 | |
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50.2 | 87 | |
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53.1 | 88 | * Red ERMAK-TT |
| 89 | * Blue - FLEX radio. "Fast" filters (167ms) | ||
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47.1 | 90 | |
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53.1 | 91 | Result: 40ms+70ms=**110ms** latency difference, **FLEX radio** **provides lower latency** |
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47.1 | 92 | |
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50.2 | 93 | [[image:1778073107052-698.png]] |
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53.1 | 95 | **Conclusions** |
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47.1 | 96 | |
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53.1 | 97 | * When using **short filters** and **DAX v1**, the latency of **FlexRadio** and **ERMAK-TT(Phoenix) ** + **EAX) **is approximately comparable. |
| 98 | * The main contribution to latency in **DAX v1** comes from the audio stack buffers and the VAC driver; in **DAX v2 **this contribution has been substantially reduced thanks to the redesigned VAC. | ||
| 99 | * In **DAX v1**, the original VAC — Virtual Audio Cable by Eugene Muzychenko was used. ([[https:~~/~~/community.flexradio.com/discussion/8027376/smartsdr-2-8-1-and-bsod>>https://community.flexradio.com/discussion/8027376/smartsdr-2-8-1-and-bsod]]) | ||
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49.1 | 100 | |
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| 103 | [[image:1778074304325-846.png]] | ||
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53.1 | 106 | * In **DAX v2**, a solution based on Thin Audio Gateway (the same author) is used, which provides smaller buffers and lower latency. |
| 107 | * **DAX v2** delivers a latency improvement of approximately **~~100 ms** compared to DAX v1. | ||
| 108 | * **We plan to migrate to a similarly architected VAC/low-latency audio engine by autumn 2026.** |