Talk:Modulation

message: Please be consistent about "Analogue" vs "Analog".  As wikipedia redirects all "Analogue" articles to "analog" I changed the spelling here to be consistent. - Xeo 14:43, 12 October 2005 (UTC)
thread_title: Spelling

message: Would one or more simple diagrams of some of these concepts help? I am able to make some new (high quality) graphics, or 'refactor' existing ones. Any ideas or requests? At the very least, I think a few graphs illustrating the carrier and signal like the one over at Amplitude modulation ? --Aidan 10:52, 20 February 2006 (UTC)
replies: text: I don't think we need to replicate the content of other articles here, no. That's why we have the other articles! We could use a system diagram or something generic and high-level like that. One that doesn't deal with a particular modulation scheme but has, you know "data source"->"modulator" -> etc (with a little bit more detail, perhaps). But then that might live better in a general communications article. -Splashtalk 19:18, 12 February 2006 (UTC)
replies: text: Mmm, I totally agree about replicating graphics. The main reason I suggest this is I think 'Modulation' is a relatively broad/high-level topic. Including image(s) in this article could help demonstrate this idea. Also, from a usability perspective, it can instantly make it clear that this article is definately not about musical modulation (some people don't read). But yeah, now that I think about it, just because an article's 'child' articles have images, doesn't mean it should. (Also, useless images are just that...) Thoughts? --Aidan 10:52, 20 February 2006 (UTC)
thread_title:  Diagrams 

message: In mobile communication systems, usually a combination of modulation techniques are used. The most common being NB-FM (for GSM), TDMA (now obsolete), FDMA, CDMA, etc.. Elaborate ur quesy/suggestion in the body with only the main theme in the title region. --Electron Kid 04:03, 22 January 2006 (UTC)
replies: text: I have no idea what you are asking, sorry. -Splashtalk 04:23, 22 January 2006 (UTC)

text: GSM uses GMSK, I've no idea what "NB-FM" is.  TDMA, FDMA and CDMA are multiple access schemes, not modulation schemes.  TDMA is not obsolete - it's used in GSM, for instance (GSM also uses FDMA).  Oli Filth 11:33, 23 August 2006 (UTC)
thread_title:  what are the modulation techniques used in mobile networks ???? 

message: A quick look around this bundle of articles is not very enlightening for an outsider. It's all incredibly difficult to penetrate. Is there a suitable entry point? Omphaloscope talk 18:42, 1 September 2006 (UTC)
replies: text: I have added some metaphores from music and numerical examples, in an attempt to give the article a popular scientific touch. But we need lots of illustrations! Mange01 01:45, 27 November 2006 (UTC)
replies: text: It still sucks.  I'm going to make the entry strike home more.  Something about modulation as being a variant of the more generally understood modification.
+ I really don't think it's unreasonable to expect and accept that some people will simply not have the level of education in the subject matter required to understand the article.  That definitely doesn't mean the article should be dumbed-down.  Then it would help ultimately no one.  — Preceding unsigned comment added by 206.208.32.2 (talk) 17:28, 13 May 2021 (UTC)
thread_title:  Too much jargon 

message: Somebody can explain modulation formats in a wireless/wireline agnostic way.
--பராசக்தி 21:35, 23 November 2006 (UTC)
thread_title:  Polarization Modulation 

message: The article doesn't explain why waves would be modulated. It doesn't explain why you would want to have a modulated wave, why an information wave is not suitable for long-range transmissions, etc. Titoxd(?!? - cool stuff) 07:36, 6 April 2007 (UTC)
replies: text: There are a few different reasons, partly depending on what the source signal is. Audio frequencies don't go through the air well as electromagnetic waves.  They do go down wires, but even in that case, modulation allows more than one signal on the same wire.  Video signals on magnetic tape are FM, as the wide frequency range is otherwise too difficult to record with required linearity. Gah4 (talk) 06:00, 27 September 2019 (UTC)
thread_title:  Why? 

message: There is two list of the digital modulation techniques. I think this section should be revised.  —Preceding unsigned comment added by 189.27.3.193 (talk) 17:20, 12 December 2007 (UTC)
replies: text: I suppose I am not surprised that there might be contradictions, as it isn't so obvious. Since wires hold voltages and currents, but not ones and zeros, it is somewhat obvious that, in the end, they must be treated as analog. One could, however, do modulation or demodulation in the digital domain, separate from the D/A or A/D conversion. This applies for both analog and digital sources. Consider a radio station broadcasting from a CD. Normally, one converts the CD digital data to an analog audio signal, and then applies that to an analog modulator.  One could, though, using digital electronics, generate a digital representation of a modulated AM or FM carrier, convert that to analog, amplify as appropriate, and feed the transmitter. Similarly, one could, in the digital domain, generate the PAM waveform from a digital source, or demodulate one converted to digital.  This process is most often included in Software-defined_radio.  (Even though most often it is done using programmable hardware.) Gah4 (talk) 17:18, 27 September 2019 (UTC)
thread_title:  digital modulation techniques 

message: Please vote at Talk:Eb/N0#Survey on which unit that should be used at Wikipedia for measuring  Spectral efficiency. For background, see the discussion at Talk:Spectral_efficiency#Bit/s/Hz and at Talk:Eb/N0#Bit/s/Hz.
Mange01 (talk) 07:21, 16 April 2008 (UTC)
thread_title:  Survey: bit/s/Hz, (bit/s)/Hz, bps/Hz or bit·s<sup>−1</sup>·Hz<sup>−1</sup> as [[Spectral efficiency]] unit? 

message: The article shows Analog, Digital, and Spread Spectrum as three types of modulation.  Analog and Digital are summarized in the article, but Spread Spectrum is not.  The article for Spread Spectrum should be summarized here to highlight the important details of that type of modulation. Also modulation in music is mentioned in the opening paragraph, but modulation in telecommunications is the subject of the article.  A link or a brief explanation of how it is used in music should be shown.  (RobPSL (talk) 02:50, 5 June 2008 (UTC)
replies: text: There is a link to Modulation (music) in the sentence you are referring to.  Oli Filth(talk) 08:03, 5 June 2008 (UTC)
thread_title:  Suggestion: Format 

message: It seems to me this article is very similar or identical in purpose and scope to the Amplitude modulation article.  Could/should they be merged? --166.70.188.26 (talk) 17:45, 30 June 2008 (UTC)
replies: text: Amplitude modulation is a specific case, this article is the general case. I believe that there is enough reason to keep both. For some rare modulation methods, it might not be worth a separate article. Gah4 (talk) 00:07, 6 December 2015 (UTC)
thread_title:  Merge? 

message: The main article could be improved with a couple paragraphs on the history of modulation.   Did it really start with telegraph wires that were turned into telephones?   How did it differ in the later years, when radio broadcasting came to be the norm?
The main article contains the following sentence:
 "Often a high-frequency sinusoid waveform is used as carrier signal to convey a lower frequency signal."
but doesn't explain the history or mathematics behind it.   Why does the waveform have to be sinusoidal?   Was that the easiest waveform to generate?   What happens when some other waveform is used?   Was there a spectacular failure or difficulty encountered by some early pioneer who tried a different waveform?  Dexter Nextnumber (talk) 03:08, 17 December 2009 (UTC)
replies: text: The first radio transmitters were spark-gap transmitter because an impulse sequence is the easiest waveform to generate. However, it is hard to detect. Transmitters generating sinusoid waveforms made it possible to build tuned receiver side filters. The tuner improves the signal-to-noise ratio and makes multiplexing possible (dividing the radio spectrum into channels). A sinusoid signal is easy to detect if the reception conditions are poor. Just like you can hear someone blowing a tone in a wistle allthough the weather may be windy, while a noisy and wide bandwidth signal is hard to detect.Mange01 (talk) 14:40, 17 December 2009 (UTC)
replies: text: Do you mean gaps like in automobile spark plugs, or distributor point gaps?   A spark of that nature would be a momentary all bands broadcast, wouldn't it?   Dexter Nextnumber (talk) 23:24, 17 December 2009 (UTC)
replies: text: See Spark-gap transmitter. I don't know how much it resembled these. And yes, it wold momentary affect large portions of the spectrum. The idea of sending impulse sequences over large portions of the spectrum is kind of reinvented in some of today's UWB proposals. Mange01 (talk) 12:06, 18 December 2009 (UTC)
thread_title:  Needed - History of Modulation  

message: Were there significant differences in the consumption of power between AM and FM in the 1920s and 1930s?   I am curious about the expenses an early station director would have had to consider, to decide which kind of modulation he would have to authorize in order to run his business.  Dexter Nextnumber (talk) 03:16, 17 December 2009 (UTC)
replies: text: Interesting question. In the 1920's, when vacuum tube amplifiers were new, getting to 100MHz at high power wasn't so easy. On the other hand, there is a lot of electrical noise around the 1MHz of the AM band, so you don't need as much power to be heard. Also, high gain antennas are easier to build (smaller) at FM frequencies than AM frequencies. Between those, I have no idea how the costs would be for transmitters or receivers. In the beginning, there weren't as many FM receivers, until it got popular enough. That is an additional consideration. Gah4 (talk) 00:23, 6 December 2015 (UTC)
thread_title:  Power requirements in the 1920s and 1930s 

message: What does it mean to multiply two waves?  188.58.66.46 (talk) 09:39, 5 March 2012 (UTC)
replies: text: If you consider, for example the voltage in a wave on a wire, or the pressure difference for a sound wave, you multiply the values from two waves. This makes it easiest to connect the theory to practice. Gah4 (talk) 00:14, 6 December 2015 (UTC)

text: More specifically, in the case of DSB-SC (double sideband suppressed carrier) the output is (proportional to) the product of the carrier and modulation input voltages. It is suppressed carrier such that the output goes to zero when there is no signal input. Gah4 (talk) 00:32, 6 December 2015 (UTC)
thread_title:  What is "multiplication"? 

message: The two leading paragraphs in the introduction give the impression that there are two different definitions of modulation in telecommunications and electronics.  Are there?  If true, it should be sourced.  If not, maybe the two paragraphs should be edited to emphasize that these are just different ways of viewing the modulation process. --ChetvornoTALK 15:05, 8 February 2014 (UTC)
thread_title:  Two definitions in introduction 

message: 1. Under "List of common analog modulation techniques", should "frequency modulation" and "phase modulation" be listed at the same level with "amplitude modulation" or they are actually a type of "angle modulation" technique?
2. "According to one definition of digital signal, the modulated signal is a digital signal. According to another definition, the modulation is a form of digital-to-analog conversion. Most textbooks would consider digital modulation schemes as a form of digital transmission, synonymous to data transmission; very few would consider it as analog transmission."
I'm not sure what this means and what is the relevance.
3. Should "Modulator and detector principles of operation" be "Modulator and demodulator principles of operation"?
4. "Non-coherent modulation methods do not require a receiver reference clock signal that is phase synchronized with the sender carrier wave. In this case, modulation symbols (rather than bits, characters, or data packets) are asynchronously transferred. The opposite is coherent modulation."
I'm not sure what the relevance of the above information with the section.
5. Should "OOK" be listed under "ASK" in the "List of common digital modulation techniques"?
6. "MSK is a particular case of the sub-family of CPM known as continuous-phase frequency-shift keying (CPFSK)".
If that is the case, "MSK" should be listed under "CPFSK".
7. "Pulse-width modulation (PWM) and Pulse-depth modulation (PDM)"
Why aren't they split on two lines?
8. Under "Analog-over-digital methods", shouldn't "ADPCM" be indented under "DCPM"?
ICE77 (talk) 06:59, 14 June 2015 (UTC)
thread_title:  Comments and questions 

message: After explaining audio tones and modems for telephones, it seems to suggest that this is different for DSL, but doesn't say why it is different. The frequencies are different, and the modulation method may be different, but otherwise they are similar enough, both being modulated in some way. Gah4 (talk) 00:19, 6 December 2015 (UTC)
thread_title:   This is similar to the technique used by dialup modems as opposed to DSL modems. 

message: Since I'm not sure if the below techniques fall under articles for 'Pulse Position Modulation' (if analog waveforms can be considered encoded data, with a clock/sample rate), or (Pulsed) 'Frequency Modulation', could pulse modulating voice using microwave transmitters possibly be included under the 'Miscellaneous modulation techniques' header?
https://en.wikipedia.org/wiki/Modulation#Miscellaneous_modulation_techniques
"Over the years, some have expressed concerns about the capability of communicating directly with humans by pulsed microwaves. In fact, earlier while studying microwave-induced auditory effects in human subjects, it was noticed that in addition to zip, click and knock sounds from exposure to single pulses of microwave radiation, short trains of rectangular microwave pulses are heard as chirps with tones corresponding to the pulse repetition frequencies [Guy et al., 1973, 1975]. It was also found that when the pulse generator was keyed manually such that each closing and opening of a push-button switch resulted in emitting a short rectangular pulse of microwave energy-transmitted digital codes (Morse code) were received and accurately interpreted by the targeted subject [Lin, 1978].
Also, soon after a system was setup for exploring the microwave auditory effect at the Walter Reed Army Institute of Research (WRAIR) [Sharp, et al., 1974], two of the principal investigators were able to demonstrate direct communication of simple speech via appropriate modulation of microwave energy [Justesen, 1975]. They tape-recorded each of the single-syllable words for digits between one and ten. The speech waveforms of each word were then converted to digital signals in such a fashion that each time an analog speech wave crossed the zero reference in the negative direction, a short pulse of microwave energy was emitted from the transmitter. By subjecting themselves to the exposure of 'speech modulated' microwave energy, the investigators reported the ability to hear, identify, and distinguish the word transmitted."
"Frey and Messenger (1973) demonstrated and Guy, Chou, Lin, and Christensen (1975) confirmed that a microwave pulse with a slow rise time is ineffective in producing an auditory response; only if the rise time is short, resulting in effect in a square wave with respect to the leading edge of the envelope of radiated radio-frequency energy, does the auditory response occur. Thus, the rate of change (the first derivative) of the wave form of the pulse is a critical factor in perception. Given a thermodynamic interpretation, it would follow the information can be encoded in the energy and 'communicated' to the 'listener'. Communication has in fact been demonstrated. A.Guy (Note 1), a skilled telegrapher, arranged for his father, a retired railroad telegrapher, to operate a key, each closure and opening of which resulted in radiation of a pulse of microwave energy. By directing the radiations as his own head, complex messages via the Continental Morse Code were readily received by Guy. Sharp and Grove (Note 2) found that appropriate modulation of microwave energy can result in direct 'wireless' and 'receiverless' communication of speech. They recorded by voice on tape each of the single-syllable words for digits between 1 and 10. The electrical sine-wave analogs of each word were then processed so that each time a sine wave crossed zero reference in the negative direction, a brief pulse of microwave energy was triggered. By radiating themselves with these 'voice modulated' microwaves, Sharp and Grove mere readily able to hear, identify, and distinguish among the 9 words."
References:
RrabEkim (talk) 03:18, 6 October 2021 (UTC)
thread_title:  Use of pulse modulation with the microwave auditory effect 

message: The 'Pulse modulation methods' section:
https://en.wikipedia.org/wiki/Modulation#Pulse_modulation_methods
Does not currently include:
https://en.wikipedia.org/wiki/Pulse-frequency_modulation
RrabEkim (talk) 20:50, 7 October 2021 (UTC)
thread_title:  Include Pulse-Frequency Modulation (PFM) under pulse modulation methods