I would like to know the specifications of the FreeDV mode.

[JH0PCF kanda]

This is JH0PCF Kanda. I am always grateful for your help.

FreeDV to become more Japanese amateur radio operator

I have some information that I would like to know in order to disseminate it.

For Japanese amateur radio, each mode of FreeDV

To operate, attach detailed specifications to the ministry that supervises wireless administration

If you do not submit an application, you will not be allowed to operate,

Currently revealed in Japan

The mode specifications of FreeDV are 700D mode, 1600 mode, 700C mode, and 2020 mode.

What I want to know is that it was implemented from Ver 1.5

700E mode specification design,

It was also implemented before

About the specification design of each mode of 800XA and 2400B.

Once this is understood, more Japanese amateur radio operators

You will be able to share information and spread FreeDV.

I will write a concrete example of what kind of information is needed.

Currently known mode specifications

700D mode

Method FDMDV2

Subcarrier modulation method 14DQPSK

Subcarrier wavenumber 14 (DQPSK)

Subcarrier frequency interval 75Hz

Data rate 1,450 bit / s (voice coding 1375bit / s, text 25bit / s, frame sync 50bits / s)

Subcarrier transfer rate 75 bit / s

Occupied bandwidth 1,000Hz

Codec CODEC2

FreeDV 1600 mode: 1275 bit / s voice coding,

25 bit / s text for callsign ID,

300 bit / s FEC, 16 x 50 baud DQPSK carrier,

Differential QPSK demodulation

FreeDV 700 (C) mode: 700 bit / s voice coding,

No FEC, 14x75 Bo QPSK Carrier,

Frequency diversity Measures against fading by diversity,

Coherent QPSK demodulation

The following is an example of FreeDV 1600 mode.

Modulation method, standard, etc. method FDMDV

Subcarrier modulation method 16DQPSK

Subcarrier frequency interval 75 Hz

Data rate 1,600 bits per second (voice coding 1,275 bits / second,

Text 25 bit / sec, FEC 300 bit

/ s) Subcarrier transfer rate

50 bits / s CODEC

Thank you.

[Mooneer Salem]

Hi Kanda,

David Rowe has some information about 700E up at http://www.rowetel.com/?p=7596. Given that it shares similarities to 700C and 700D I feel like there should be enough to provide whatever the authorities in Japan require but of course, I'm not familiar enough with the regulatory situation there to comment for sure. Hopefully it helps regardless.

Thanks,

-Mooneer K6AQ

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[Bruce Perens]

Kanda-san,

Please submit the full source code, and see if they accept it. Their goal in asking for a specification is to be able to decode the transmission. Obviously source code achieves this, and is arguably better than a paper specification that they would then have to implement in some way.

This is important to the Open Source community. I appreciate your patience.

    Many Thanks

    Bruce

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Bruce Perens - CEO at stealth startup. I'll tell you what it is eventually :-)

[David Rowe]

Hi Kanda,

I'll type something up in the FreeDV Manual this weekend using your examples below as a guide to the level of detail required.  I feel it's useful to collate this information somewhere as a general, high level reference. 

As Mooneer and Bruce suggest, for those who want more detailed information there is the source code (in reference Octave and C code form), a spreadsheet that describes the design of the newer waveforms, numerous blog posts, and the codec2/README_*.md files.

- David

[David Rowe]

Turns out I had already documented most of the the information required by Kanda in this overview of the FreeDV technology.  Might also be a useful reference for others:

  https://github.com/drowe67/codec2/blob/master/README_freedv.md

BTW the FreeDV User Manual which is now available in HTML and PDF form - see links from http://freedv.org

- David

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[JH0PCF kanda]

I'm late to thank David

Inquire about the specifications of FreeDV

When you answered, based on that material

Create a page called FreeDV Specifications

On the page of JARL, an amateur radio organization that represents Japan

I was able to get it posted.

Display may be difficult without Japanese fonts

Please grasp the atmosphere

JARL

https://www.jarl.org/Japanese/2_Joho/2-2_Regulation/datetushin_shogen.pdf

2021年2月14日日曜日 6:41:48 UTC+9 DavidRowe:

[David Rowe]

Hi Kanda,

Thanks, that looks great.  I am pleased the information as useful and has been published by the JARL.

Cheers,
David

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