OpenLLM-France/wikimedia huggingface dataset:
# Communication Systems/Baseband and Broadband Signals

It is important to know the difference between a baseband signal, and a broad band signal. In the Fourier Domain, a baseband signal is a signal that occupies the frequency range from 0 Hz up to a certain cutoff. It is called the baseband because it occupies the base, or the lowest range of the spectrum.
In contrast, a broadband signal is a signal which does not occupy the lowest range, but instead a higher range, 1 MHz to 3 MHz, for example. A wire may have only one baseband signal, but it may hold any number of broadband signals, because they can occur anywhere in the spectrum.

## Wideband vs Narrowband

in form of frequency modulation. wideband fm has been defined as that in which the modulation index normally exceeds unity.

## Frequency Spectrum

A graphical representation of the various frequency components on a given transmission medium is called a frequency spectrum.
# Communication Systems

* For the book on inter-personal communications theory, see: Communication Theory
* A printable version of Communication Systems is available.
* A PDF version is available. (info)
* This book requires that you first read Signals and Systems.
* This book requires Data Coding Theory as a corequisite.
* This book is intended for advanced readers.

## Introduction

This book will eventually cover a large number of topics in the field of electrical communications. The reader will also require a knowledge of Time and Frequency Domain representations, which is covered in-depth in the Signals and Systems book. This book will, by necessity, touch on a number of different areas of study, and as such is more than just a text for aspiring Electrical Engineers. This book will discuss topics of analog communication schemes, computer programming, network architectures, information infrastructures, communications circuit analysis, and many other topics.
This book is still in an early stage of development. Many topics do not yet have pages, and many of the current pages are stubs. Any help would be greatly appreciated.

## Table of Contents

* Communications Introduction
* Communications History

### System Examples

This section will provide a brief overview of the more common communications systems in use today. The demarcation between these systems is quite artificial since a wireless VoIP Internet connection may be a combination of all of these individual systems.
* Telephone System
* Cellular Systems
* Packet Data Systems
* Satellite Systems
* Microwave Systems
* Fiber Optic Systems

### Communications Basics

This section will examine some theory common to many communication systems. Examples are, what constitutes a signal, information, channels, multiplexing etc.
* Baseband and Broadband Signals
* Time-Division Multiplexing
* Frequency-Division Multiplexing
* Voltage-Controlled Oscillators (VCO)
* Envelope Filters (Envelope Detectors)
* What is Modulation?
* Analog vs. Digital
* Communication Mediums
* Coherent Receivers

### Analog Modulation

This section will examine the nature and conveyance of continuously varying information signals.
* Analog Modulation Introduction
* Amplitude Modulation (AM)
* Frequency Modulation (FM)
* Phase Modulation (PM)
* FM and PM Generalization
* AM Receivers

### Digital Modulation

This section considers the nature and encoding of discrete information signals.
* Pulse Amplitude Modulation (PAM)
* Binary Modulation Schemes
* M-ary Modulation Schemes
* Quadrature Amplitude Modulation (QAM)
* Noncoherent Receivers
* Line Codes

### Transmission

This section examines various communications media and its characteristics. Any communication system may contain one or more of these media types.
* Wave Propagation
* Antennas
* Noise Figure
* Wired Transmission
* Wireless Transmission
* Space-Division Multiplexing
* Fading Channels

### Appendices

* IEEE 802 Working Groups

### Resources and Licensing

* Resources
* Licensing
# College Survival Guide/Social Life
## Hazing

Some campus organizations will have an initiation. Some of these rituals are relatively harmless, such as a short chant or oath. However when these initiations include hazing, they have gone too far, and can harm yourself, the organization, and the rest of the campus community. For example if a group asks you to streak across campus, you may impress that specific group by doing that. However, to everyone else on campus, you'll be the person who publicly ran nude in front of students, visiting tour groups, professors, and administrative staff. Even if you somehow evade the campus police, someone is probably going post a video of it online that could haunt you professionally later. Serious private hazing is no better, and there is usually several deaths in the United States every year which can be attributed to hazing incidents.

## Guide to drinking

In most college towns, drinking is a part of life, and often a major part of the local culture.
A good drink is meant to be savored with friends over a period of time. Know your limits, both physically and financially - there's nothing wrong with keeping it to a single drink for the night. Don't leave your drink unattended, and make sure Alcohol is ok to drink with any medications you might be on.
Casual drinking can be a nice way to spend time with friends, but drinking too much is bad for your academic career, and life in general. Poor quality sleep and hangovers can make classwork the next day difficult. Drinking a lot of alcohol frequently gets expensive fast, and getting your stomach pumped or dealing with liver damage isn't fun.
If you want to abstain from drinking or just don't feel like drinking on some nights, that is absolutely fine. Hanging out with inebriated friends, watching drunk antics while sober, and safely acting as their designated driver can be its own unique reward.

### ABV

Keep in mind that some alcohol is much stronger than others: a glass of light beer and a glass of vodka are not equivalent. Alcohol by Volume is the measurement of how much alcohol is in a drink. In general, low ABV drinks are enjoyed by themselves, and high ABV drinks are served in smaller amounts, or diluted as part of a mix, such as in a cocktail.
Below is a quick guide to typical ABV. Each individual drink has its own value, and some drinks vary significantly.
* Beer and cider is around 6% ABV or less.
* Wine and mead is about 12% ABV.
* Liqueurs range from 15% ABV to 50% ABV.
* Whisky, Rum, Brandy, and Gin typically range 40% ABV - 60% ABV.
* Vodka and Absinthe can range from 40% ABV to 90% ABV.
# College Survival Guide/Studying
## Going to the Library

Going to school and staying away from home is the best possible thing to do if you want to study. Being at home, a person may be tempted to turn on the television or play around on the internet. This is why going to a library is recommended. Make sure you make a meal for yourself so you can study for a few hours there.
Also, unless you really, really have to use it, stay away from the internet and a computer. Sometimes, when a person gets on the internet, they will become distracted in listening to music, reading a blog, etc., instead of doing school work. Staying away from a computer is often a good strategy when studying in a library.

### Finding a quiet space

When inside the library, find a quiet place to sit. Make sure this area has ample lighting; lighting has an effect on the circadian system of the human body and keeps the mind awake and active.
Of course, a library is not always the quietest place around, if the surroundings are not controlled. Cell phones are the demons of today's world when one wishes to have silence. Colleges are also not without their chatty individuals. A recommendation is to get the type of ear muffs a person wears when shooting a gun. Don't buy a gun, or use a gun in school; just buy the ear muffs used. The ear muffs, at times, are better than noise-canceling headphones. Ear muffs greatly reduce the sound level of your surroundings.

## See Also

* How to pass a course
# College Survival Guide/Testing for College Credit

This part of the book is directed more toward United States students. However, there may be tests in which other students of different regions may take.
Make sure the credits you obtain are accepted by the institution you plan on going to before you acquire them.
* Some High School courses, such as AP classes, allow you to gain college credit.
* Some tests like the CLEP let you test out of classes.
* Some Colleges offer classes can be taken while in high school at subsidized rates.
* Some online course platforms offer college credit through an accredited partner institution. One such platform is edX, which was founded by Harvard and MIT. Be wary of fraudulent programs and degree mills while looking online. Always check accreditation.

## External Links

* edX courses avalible for credit

## References

* ↑ "About Us". edX. Retrieved 19 December 2020.
# Cg Programming/Unity/Lighting Textured Surfaces

This tutorial covers per-vertex lighting of textured surfaces.
It combines the shader code of Section “Textured Spheres” and Section “Specular Highlights” to compute lighting with a diffuse material color determined by a texture. If you haven't read those sections, this would be a very good opportunity to read them.

## Texturing and Diffuse Per-Vertex Lighting

In Section “Textured Spheres”, the texture color was used as output of the fragment shader. However, it is also possible to use the texture color as any of the parameters in lighting computations, in particular the material constant $k_{\text{diffuse}}$ for diffuse reflection, which was introduced in Section “Diffuse Reflection”. It appears in the diffuse part of the Phong reflection model:
$I_{\text{diffuse}}=I_{\text{incoming}}\,k_{\text{diffuse}}\max(0,\mathbf {N} \cdot \mathbf {L} )$
where this equation is used with different material constants for the three color components red, green, and blue. By using a texture to determine these material constants, they can vary over the surface.

## Shader Code

In comparison to the per-vertex lighting in Section “Specular Highlights”, the vertex shader here computes two additional output colors: diffuseColor and specularColor, which use the semantics TEXCOORD1 and TEXCOORD2.
The parameter diffuseColor is multiplied with the texture color in the fragment shader and specularColor is just the specular term, which shouldn't be multiplied with the texture color. This makes perfect sense but for historical reasons (i.e. older graphics hardware that was less capable) this is sometimes referred to as “separate specular color”; in fact, Unity's ShaderLab has an option called “SeparateSpecular” to activate or deactivate it.
Note that a property _Color is included, which is multiplied (component-wise) to all parts of the diffuseColor; thus, it acts as a useful color filter to tint or shade the texture color. Moreover, a property with this name is required to make the fallback shader work (see also the discussion of fallback shaders in Section “Diffuse Reflection”).
In order to assign a texture image to this shader, you should follow the steps discussed in Section “Textured Spheres”.

## Summary

Congratulations, you have reached the end. We have looked at:
* How texturing and per-vertex lighting are usually combined.
* What a “separate specular color” is.

## Further reading

If you still want to know more
* about fallback shaders or the diffuse reflection term of the Phong reflection model, you should read Section “Diffuse Reflection”.
* about per-vertex lighting or the rest of the Phong reflection model, i.e. the ambient and the specular term, you should read Section “Specular Highlights”.
* about the basics of texturing, you should read Section “Textured Spheres”.
< Cg Programming/Unity
# Cherokee/Resources
## Old and Unclassified Links

* Cherokee NT Online (Cherokee Bible Digitalization Project)
* English/Cherokee Dictionary
* Cherokee Language Lessons
* Cherokee Language Online
* Cherokee Language Yahoo Group
* Echota Cherokee Revitalization Project
* Cherokee Wiktionary, ,
# Cherokee/Syllabary

Before you continue with learning the Cherokee language, it is important to be able to read and write in Cherokee. That is what this lesson will help you with.
The Cherokee language does not use a alphabet, but a syllabary. That means each Cherokee symbol represents a syllable, not just a consonant or a vowel. Because of this, Cherokee symbols are arranged in a chart, with a column for each Cherokee vowel and a row for each Cherokee consonant.
Below is a chart of the Cherokee Syllabary:
Sounds Represented by Vowels
IPA-sound-representations in.
    a (as in father, or short as in rival)[a~ɑ]
    e (as in hate, or short as in met)[ɛ~e]
    i (as in pique, or short as in pit)[i~ɪ]
    o (as in law, or short as in not)[ɔ~o]
    u (as in fool, or short as in pull)[ʊ~u]
    v (as in but, nasalized)[ʌ̃]

## Exercises

/Yet to come: A good exercise would be to have a whole bunch of words in Cherokee syllabary, and the student can transliterate them, and then check the answer's--and vice versa./
* Example: o-si-yo (hello). First write the syllable for o then si then yo.
* Example 2: ᎠᎹ(a-ma') (water). First write the syllable for Ꭰ(a) and then for Ꮉ(ma).
Learning the Cherokee Syllabary is a important part of learning the Cherokee language. Hopefully after these exercises you have gotten familiar with them. You'll continue to get more and more familiar with constant use, and all the next lessons will be in the Syllabary. Don't get discouraged though, if you don't completely know the Syllabary yet. The next few lessons will have the Latin transcription side by side with the syllabary to help you. But pay attention to the syllabary, as the transliteration will slowly be phased out.
One of the better ways to learn the Syllabary is by writing the letters out individually by dictation.
One source of Cherokee Syllabary dictation is: http://www.cherokeelessons.com/Super-Cherokee-Syllabary-Dictation-Practice/
# Cherokee/Pairs

"Critical pairs" is a concept that may help you remember certain vocabulary by emphasizing the typically one-to-two correspondence between some English and Cherokee terms. In other words, a critical pair refers to either the two ways in Cherokee that a single concept in English is expressed, or the one way that two English concepts are expressed in Cherokee. The number two is not important—it could be three or even more. The point is that you should ideally be conscious of the cases in which the correspondence of terms between the two languages is not one-to-one.
Cherokee Terms that English Splits in Meaning :
| English Terms | Cherokee Term | Notes |
| table, chair | gaasgilo | locative: gaasgilv4qi |
English Terms that Cherokee Splits in Meaning :
| English Term | Cherokee Terms | Basis of Split | Notes |
| sleep | lh (Ga, G, ss) [íh, vv́na, ih, NA, vnhd]; hlín (A, sp) [-, NA, -, NA, NA] | Singular and plural use different roots. | Aspiration class for hlín is unclear but irrelevant, though underlyingly it probably mirrors lh's G (glottal) class and thus might be better spelled lhín. |
# Cherokee/Revitalization

Since 2001, the Cherokee Nation has operated the Cherokee Immersion School in Park Hill, Oklahoma, serving grades K-8. The EBCI also runs a K-6 immersion school since 2004, the New Kituwah Academy. Beyond these immersion schools, language classes for adults exist, as well as master-apprentice programs that pair beginning learners with fluent speakers.
Unfortunately, the generation gap—referring to the current parents’ generation who did not grow up speaking Cherokee—makes it difficult for children to use Cherokee on a daily basis outside of school. Adult learners also have significant trouble achieving proficiency in Cherokee due to the lack of good resources in language classes.
# Cherokee/Notebook

"Simple Phrases" section is old.
Below we keep track of important vocabulary items not yet incorporated into the lessons. Eventually it would be good to have an index of vocabulary stating which lesson introduces each word. This could go in the dictionary. This current system should probably be temporary but I had to create it just to start somewhere.
Consider: Upon adding tone/length and usage information for an item below (and anyone can do this at anytime), mark that item as ready to move to the dictionary. (You can even move it there if you format it consistently. Right now there is no standard format so we should just mark it as ready to move using boldface.)

## Important Vocabulary
### From Cherokee Narratives

sagwu iyuwakdi = one time
nidulsiníisv = every night
nigvwsdv = it seemed
vsgí dehv = that D-"have"-EXP (??) - "well that" - clarify meaning
ilv4sgi = a few
>ilvsgi winusv4hla = a few days later
> ilvsgi naniqv = a few of them
do ase [V] = really perhaps - used before verb (nulstane) in narrative - adverbial - used here to express belief (in the legitimacy of something heard)
dlv [Num] = about/approximately
>dlv ade = about probably
kilagwu iyvda = immediately (gloss: immediately-just length.of.time)
hle4ga = awhile
agw-os-el-v = he/me-say-DAT-EXP = he said to me / he told me
ayvhnó noógwu [V] (gloss: I-and then) = and then I ...
ak-sgásdaneh-v ú-lenvh-v (1B-get.scared-EXP 3B-start-EXP) = I started to get scared; note third person marking on "start" instead of first person i.e. "it started, that I got scared". I didn't start technically—the situation started that I got scared.
elisgini = although (cf. néélagiihnv)
kilo gajiyoligi = someone(s) I know
[V] [INF] ugv23wahli (CN 35) = to V in order that INF

## Verbs Related to Speech, Talking, Etc.

gawóóniha (vi) = he's speaking (RRD: speak, talk)
kanééga (vi) = he's speaking/answering
àdiha (vt) = he's saying it
gòséha (vt) = he's saying to him
nigaweqa (vi?) = he's saying it; it's barking, meowing, whinnying, or cooing; RRD: say, utter
kanoohéha (vt) = he's telling it
(RRD only) ahlinohéhdiha = he's speaking to him

## Simple Phrases

    Gado hadvne (what are you doing?)
    dagilawisdane (I am working)
    tsayosihas (are you hungry?)
    v v agiyosi (yes I am hungry)
    tsadulis hawiya? do you want meat?
    v v hawiya aquaduli yes meat I want
    kawi tsadulis? Do you want coffee? (lit: coffee you want it?)
    v v kawi aquaduli yes coffee I want it
    ugodidas agasga ahnai?----alot it is raining there?
    tla tlayagasga-- --no it is not raining
    Okay Ho wa
    Thank you Wa do
    Yes vv ii
    No Thla
    I don't know Thla ya gwan ta
# Cherokee/On Tone
## Isn't it exceptionally difficult to learn a tonal language?

Yes, if you come into it with the mindset that the way intonation words in a tonal language like Cherokee is similar to how it works in another language, whether or not it is tonal.
English, for example, has a stress system not considered “tonal” but that definitely has largely predictable changes in pitch. Each word has a stressed syllable usually pronounced with a higher pitch. Also, in English you can sometimes use a rising intonation to indicate that you are asking a question. These patterns of intonation must be thought of as characteristic of English, not language in general. I cannot stress enough that you have to lose all preconceived notions of pitch movement before you tackle a language like Cherokee, which has a highly involved system of pitch.
The tonal system of Cherokee is very logical but there are many rules that can take a long time to internalize. I say this even as a native speaker of Mandarin, another tonal language. In my experience, knowing Mandarin does not directly help with learning Cherokee tonology, at least in the long run, because the tonal system is so different. Maybe in the short run I am able to better grasp certain concepts, but these concepts can all be learned by anyone capable of listening and logical reasoning. Learning Cherokee tonology is, matter-of-factly, quite difficult. Mentally prepare yourself for this, but do not be discouraged. I speak from experience that with time, you will internalize more and more of the pitch system to the point that you barely have to think about it if you persevere long enough to ride out the learning curve to the end stage.
# Cherokee/Structural Nuggets

These "structural nuggets" refer to elements in the Cherokee language categorized as units of structure, as opposed to content words like nouns, for example. As such, the words or word parts found here do not solely belong to one part of speech. These "nuggets" are like the glue holding much of the language together!
Each nugget is presented in a boldface header, followed by a line defining it. Uppercase abbreviations such as ADJ for "adjective" are used to represent variable words or word parts, while lowercase Cherokee text represents invariable elements within the nugget.
Following the definition, you may find examples.
At the bottom of each entry you may find questions whose answers are unclear to the writers of this book. We empower you to ask these questions to native speakers of Cherokee and to document the answers in the Discussion section for this page, found at the top of the screen to the right of the tab that says "Book." You are always encouraged to ask for and document other ways to express the same idea for every nugget.

## Abbreviations

ADJ = adjective
S = subject
S1 = subject number 1
V = verb
V1 = verb number 1
CSP = citation for Cherokee Speech Patterns by JW Webster

## Related to Adjectives
### ADJ + jigi

the (possibly also "a") ADJ one
   giígágẽ j-igi
   red REL-be
   the red one
   CSP 22
Questions: How do you say "the red ones" or "some red ones"?

### ADJ -yú

-ly
One way to form adverbs from adjectives, equivalent to the English suffix -ly, is to add -yú to the end of the adjective.
If the adjective ends in -i, the /i/ lengthens and gets a rising tone in anticipation of the high tone on the suffix -yú.
   uusganõli > uusganõliíyú
   slow > slowly
   CSP 23

## Related to Clauses
### S1 agvvyĩ V1 si ni- V2 -ṽna(wú) S2

S1 V1 before S2 V2
One way to express that an action happens before another action is to use this structure.
   maági agvvyĩ uùhnigíisééqi si núúluhjṽnawú uweej ageéhya
   Mark first 3SG.B-left still without-3SG.B-arriving 3SG.B-child woman
   Mark left before his daughter arrived.
   CSP24