Talk:Frequency-shift keying

message: Can someone with knowledge of DFSK add information on that to this page?  —Preceding unsigned comment added by 128.253.139.181 (talk) 01:28, 1 April 2010 (UTC)

message: oh
A type of FSK that I have used for signalling in the past consists of a '1' being represented by a single cycle of a frequency f, and a '0' by 1.5 cycles of frequency f + f/2, phase continuous (typical frequencies would be 1200Hz and 1800Hz). It's a very neat and compact scheme, very easy to synthesise, with every bit period being equal, and very easy to decode, counting zero-crossings. I always though this was called FFSK, with the extra F standing for 'Fast', but currently there is no article about this. Is it perhaps known by another name? Graham 11:46, 8 February 2006 (UTC)
replies: text: Yes.  FFSK is equivalent to MSK. Oli Filth 14:57, 21 August 2006 (UTC)
replies: text: No. FFSK is equivalent to what the fine article calls "Audio FSK"  Ok, to be fair, there is a problem here that the same term is used to mean different things. but could we try to make this more clear in tfa? (sorry at the moment i have no clear idea how).  — Preceding unsigned comment added by 194.209.214.225 (talk) 13:56, 18 August 2011 (UTC)
thread_title:  FFSK? 

message: I think the article is wrong about the bit rate to frequency shift ratio. The difference between the higher and lower frequency (i.e., twice the frequency shift) is equal to <I>half</I> the bit rate.
The formula for the frequency shift \Delta F is
:\eta = 2\, \Delta F\, T\; ,
where 1/T is the bit rate, \Delta F is the frequency shift and the modulation index \eta = 0.5 for MSK. Hence, the difference between the higher and lower frequency is
:2\, \Delta F = 0.5\, \frac{1}{T}\; .--Drizzd 13:13, 9 July 2006 (UTC)
replies: text: Indeed.  I've altered this. Oli Filth 14:52, 21 August 2006 (UTC)
thread_title:  MSK 

message: Need a diagram for this to be useful in the article. I may do this myself if I have time.
The greatest single reason for the widespread use of FSK is its simple implementation. All that is required is an oscillator whose frequency can be switched between two preset frequencies. This can be easily achieved using the 555 timer IC. As the carrier signal is shifted between two preset frequencies, hence this technique of signal modulation got the name FSK.
The frequency corresponding to logic 0 and 1 are called 'space' and 'mark' frequency respectively. The FSK generator is constructed using a 555-timer in astable mode, with its frequency controlled by the state of a PNP transistor. 150Hz is the standard frequency at which data input can be transmitted.
When input is logic 1, the transistor is off. The capacitor then charges through (RA+RB) up to 2/3Vcc. Then it discharges through R<Sub>B</sub> up to 1/3Vcc. This exponential charging-discharging continues as long as input is logic 1.
  Mark Frequency =  1.44 \over {Ra+Rb}  = 1070 Hz
When input is logic 0, the PNP transistor is on (saturated), connecting RC across RA. Hence frequency obtained is:
  Space frequency =  1.44 \over {Ra||Rc + Rb}  = 1270 Hz
Hence by proper selection of resistors, the mark and space frequencies can be selected. The difference between 1070 and 1270 Hz is of 200 Hz and is called 'frequency drift'.
—Preceding unsigned comment added by Ktims (talk • contribs) 05:52 24 OCT 06
No problem. Btw, which program do u use for makin ccts, or are u on bitmap too? Xcentaur 07:53, 24 October 2006 (UTC)
thread_title:  Implementation Example - moved from page 

message: A description of "incremental frequency keying" has recently been added.  However, a Google search reveals only 39 hits, so I'm not sure it's particularly notable or widely used.  Any thoughts?  Oli Filth(talk) 01:01, 7 December 2007 (UTC)
replies: text: I see that Google gives 313 hits for "differential frequency shift keying". Is that notable enough?
I agree that IFK is not notable enough to give an article of its own.
However, I've been told that "The particular topics and facts within an article are not each required to meet the standards of the notability guidelines." -- WP:NNC.
--75.19.73.101 (talk) 06:48, 13 December 2007 (UTC)
thread_title:  Incremental frequency keying? 

message: Is not yodeling a form of fsk?
SyntheticET (talk) 04:00, 14 August 2008 (UTC)
thread_title:  acoustic fsk 

message: As both FSK and Continuous-phase frequency-shift keying (CPFSK) are a special form of frequency modulation, shouldn't CPFSK be mentioned in this article? What about 4-level Continuous FM (C4FM) - is this the same as CPFSK? --Dmitry (talk•contibs) 09:43, 26 March 2012 (UTC)
replies: text: I agree, so I added a brief mention of CPFSK and C4FM to this article. --DavidCary (talk) 18:18, 28 January 2015 (UTC)
thread_title:  Continuous Phase Frequency-Shift Keying 

message: I have added some references for modem implementations, added markers for necessary citations and moved the MSK stuff to the corresponding subpage.  — Preceding unsigned comment added by 2A4Fh56OSA (talk • contribs) 19:03, 29 December 2012 (UTC)
thread_title:  Added References and Moved MSK 

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thread_title:  External links modified 

message: Three questions:  1) What kind of FSK is used in a Weitbrecht Modem as used in the Telecommunication Devices by Deaf people, known by the abbreviation TTY or TDD?  
2) When was the first FSK introduced for telephonic communication?  
3) Why did no telephone company develop a device similar to Weitnrecht Modem already in the late 19th or early 20th century to enable deaf people to use telephone?  74.104.144.152 (talk) 15:45, 13 July 2019 (UTC)
thread_title:  Weitbrecht Modem 

message: What is the "LDM-2 low deviation modulation" mentioned in the NT (cassette) article?
Should this "frequency-shift keying" article mention it?
--DavidCary (talk) 03:04, 29 January 2022 (UTC)
thread_title:  low deviation modulation