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1 -Измерение задержки (latency) в локальном удаленных режимах (EAX, USB) и справнение c Flex radio (DAX v2)
1 +Измерение задержки (latency) в удаленном (EAX, USB) и локальном режимах и сравнение c Flex radio (DAX v2)
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1 -Измрение внутреннйе задержки трансисевра ( от RF входа до выхода адуио на наушники)
1 +== Internal latency measurement of the ERMAK-TT transceiver ==
2 2  
3 +* Transmit mode (microphone input -> RF output): **45ms**
3 3  
4 -
5 +
6 +
7 +[[image:1777980550259-754.png]]
8 +
9 +
10 +* Receive mode (RF modulator output -> headphone output): **52ms**
11 +
12 +
13 +
14 +[[image:1777980668036-257.png]]
15 +
16 +
17 +== Internal latency measurement of FLEX radio ==
18 +
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/]]
22 +
23 +
24 +
25 +[[image:1778007502882-224.png]]
26 +
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"]]
28 +
29 +
30 +[[image:1778007575902-770.png]]
31 +
32 +
33 +
34 +[[image:image.png]] [[image:https://us.v-cdn.net/6032377/uploads/OB7NPE9JDLNX/image.png||alt="image.png"]]
35 +
36 +
37 +Thanks to [[Mike-VA3MW>>url:https://community.flexradio.com/profile/Mike-VA3MW]] and [[W7NGA>>url:https://community.flexradio.com/profile/W7NGA]]
38 +
39 +
40 +== Total latency measurement of the ERMAK-TT transceiver + EAX (USB) ==
41 +
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.
43 +
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.
45 +
46 +1. [[EAX audio control - release history>>https://sdr-ermak.com/xwiki/bin/view/Main/ERMAK-TT/EAX%20aduio%20control%20utility%20releases/]]
47 +1. [[EAX VAC Windows 10>>https://nx8619.your-storageshare.de/s/pdeEJr5mG4ix7PQ?dir=/EAX%20VAC]]
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/]]
50 +
51 +
52 +
53 +* Receive mode (RF modulator output -> EAX -> PC audio output): **197ms**
54 +
55 +
56 +
57 +[[image:1778050748939-595.png]]
58 +
59 +
60 +* Receive mode (RF modulator output -> USB audio -> PC audio output): **220ms**
61 +
62 +
63 +
64 +[[image:1778051095734-567.png]]
65 +
66 +
67 +== Total latency measurement of the ERMAK-TT transceiver + EAX (USB) and Flex radio in remote mode ==
68 +
69 +**Measurement program**
70 +
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**
73 +
74 +**Measurement subject:**
75 +Reception of one-second pulses at 4999 kHz
76 +
77 +[[image:1778072528651-371.png]]
78 +
79 +
80 +* Red ERMAK-TT
81 +* Blue - FLEX radio. "Fast" filters (51ms)
82 +
83 +Result: 104ms-70ms=**30ms**, ** ERMAK-TT provides lower latency**
84 +
85 +[[image:1778072986007-908.png]]
86 +
87 +
88 +* Red ERMAK-TT
89 +* Blue - FLEX radio. "Fast" filters (167ms)
90 +
91 +Result: 40ms+70ms=**110ms** latency difference, **FLEX radio** **provides lower latency**
92 +
93 +[[image:1778073107052-698.png]]
94 +
95 +**Conclusions**
96 +
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]])
100 +
101 +
102 +
103 +[[image:1778074304325-846.png]]
104 +
105 +
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.**
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