Pengertian Sinyal Analog

Sinyal analog / Isyarat Analog adalah sinyal data dalam bentuk gelombang yang kontinyu, yang membawa informasi dengan mengubah karakteristik gelombang. Dua parameter/ karakteristik terpenting yang dimiliki oleh isyarat analog adalah amplitude dan frekuensi. Isyarat analog biasanya dinyatakan dengan gelombang sinus, mengingat gelombang sinus merupakan dasar untuk semua bentuk isyarat analog.

Gelombang pada Sinyal Analog yang umumnya berbentuk gelombang sinus memiliki tiga variable dasar, yaitu amplitudo, frekuensi dan phase.• Amplitudo merupakan ukuran tinggi rendahnya tegangan dari sinyal analog.• Frekuensi adalah jumlah gelombang sinyal analog dalam satuan detik.• Phase adalah besar sudut dari sinyal analog pada saat tertentu.

Analog and Digital Signals

Sound is naturally an analog signal. An analog signal is continuous, meaning that there are no breaks or

interruptions. One moment flows into the next. If you were to hum a descending note, people hearing you

would be able to detect the change in pitch, but not point to specific moments when the pitch jumped from

one note to the next.

Digital signals are not continuous. They use specific values to represent information. In the case of sound,

that means representing a sound wave as a series of values that represent pitch and volume over the

length of the recording. In a primitive digital recording of that descending note you hummed, you'd hear a

single long sound as a collection of shorter sounds.

Some audiophiles argue that because analog recording methods are continuous, they are better at

capturing a true representation of sound. Digital recordings can miss subtle nuances. But as digital

recording processes improve, digital devices can use higher sampling rates with greater precision.

Although the signal still isn't continuous, the high sampling rate can create a sound similar to the original

source.http://electronics.howstuffworks.com/digital-versus-analog1.htm

Signals are passed between devices in order to send and receive information, which might be video,

audio, or some sort of encoded data. Usually the signals are transmitted through wires, but they

could also pass through the air via radio frequency (RF) waves. Audio signals, for example might be

transferred between your computer’s audio card and speakers, while data signals might be passed

through the air between a tablet and a WiFi router.

Analog Signal Graphs

Because a signal varies over time, it’s helpful to plot it on a graph where time is plotted on the

horizontal, x-axis, and voltage on the vertical, y-axis. Looking at a graph of a signal is usually the

easiest way to identify if it’s analog or digital; a time-versus-voltage graph of an analog signal should

be smooth and continuous.

While these signals may be limited to a range of maximum and minimum values, there are still an

infinite number of possible values within that range. For example, the analog voltage coming out of

your wall socket might be clamped between -120V and +120V, but, as you increase the resolution

more and more, you discover an infinite number of values that the signal can actually be (like 64.4V,

64.42V, 64.424V, and infinite, increasingly precise values).

Example Analog Signals

Video and audio transmissions are often transferred or recorded using analog signals. Thecomposite

video coming out of an old RCA jack, for example, is a coded analog signal usually ranging between

0 and 1.073V. Tiny changes in the signal have a huge effect on the color or location of the video.

An analog signal representing one line of composite video data.

Pure audio signals are also analog. The signal that comes out of a microphone is full of analog

frequencies and harmonics, which combine to make beautiful music.

https://learn.sparkfun.com/tutorials/analog-vs-digital/analog-signals

Digital SignalsDigital signals must have a finite set of possible values. The number of values in the set can be

anywhere between two and a-very-large-number-that’s-not-infinity. Most commonly digital signals

will be one of two values – like either 0V or 5V. Timing graphs of these signals look like square

waves.

Or a digital signal might be a discrete representation of an analog waveform. Viewed from afar, the

wave function below may seem smooth and analog, but when you look closely there are tiny

discrete steps as the signal tries to approximate values:

That’s the big difference between analog and digital waves. Analog waves are smooth and

continuous, digital waves are stepping, square, and discrete.

https://learn.sparkfun.com/tutorials/analog-vs-digital/digital-signals

Analog Electronics

Most of the fundamental electronic components – resistors, capacitors, inductors, diodes,

transistors, and operational amplifiers – are all inherently analog. Circuits built with a combination of

solely these components are usually analog.

Analog circuits are usually complex combinations of op amps, resistors, caps, and other

foundational electronic components. This is an example of a class B analog audio amplifier.

Analog circuits can be very elegant designs with many components, or they can be very simple, like

two resistors combining to make a voltage divider. In general, though, analog circuits are

much more difficult to design than those which accomplish the same task digitally. It takes a

special kind of analog circuit wizard to design an analog radio receiver, or an analog battery charger;

digital components exist to make those designs much simpler.

Analog circuits are usually much more susceptible to noise (small, undesired variations in voltage).

Small changes in the voltage level of an analog signal may produce significant errors when being

processed.

Digital Electronics

Digital circuits operate using digital, discrete signals. These circuits are usually made of a

combination of transistors and logic gates and, at higher levels, microcontrollers or other computing

chips. Most processors, whether they’re big beefy processors in your computer, or tiny little

microcontrollers, operate in the digital realm.

Digital circuits make use of components like logic gates, or more complicated digital ICs (usually

represented by rectangles with labeled pins extending from them).

Digital circuits usually use a binary scheme for digital signaling. These systems assign two different

voltages as two different logic levels – a high voltage (usually 5V, 3.3V, or 1.8V) represents one

value and a low voltage (usually 0V) represents the other.

Although digital circuits are generally easier to design, they do tend to be a bit more expensive than

an equally tasked analog circuit.

https://learn.sparkfun.com/tutorials/analog-vs-digital/analog-and-digital-circuits

Analog adalah sinyal data dalam bentuk gelombang yang yang kontinyu, yang membawa informasi dengan mengubah karakteristik gelombang. Dua parameter/karakteristik terpenting yang dimiliki oleh isyarat analog adalah amplitude dan frekuensi. Gelombang pada sinyal analog yang umumnya berbentuk gelombang sinus memiliki tiga variable dasar, yaitu amplitudo, frekuensi dan phase. Amplitudo merupakan ukuran tinggi rendahnya tegangan dari sinyal analog. Frekuensi adalah jumlah gelombang sinyal analog dalam satuan detik. Phase adalah besar sudut dari sinyal analog pada saat tertentu.

Analog disebarluaskan melalui gelombang elekromagnetik (gelombang radio) secara terus menerus, yang banyak dipengaruhi oleh faktor ”pengganggu”. Analog merupakan bentuk komunikasi elektromagnetik yang merupakan proses pengiriman sinyal pada gelombang elektromagnetik dan bersifat variable yang berurutan. Jadi sistem analog merupakan suatu bentuk sistem komunikasi elektromagnetik yang menggantungkan proses pengiriman sinyalnya pada gelombang elektromagnetik.

Digital merupakan sinyal data dalam bentuk pulsa yang dapat mengalami perubahan yang tiba-tiba dan mempunyai besaran 0 dan 1.

Sinyal digital hanya memiliki dua keadaan, yaitu 0 dan 1, sehingga tidak mudah terpengaruh oleh derau, tetapi transmisi dengan sinyal digital hanya mencapai jarak jangkau pengiriman data yang relatif dekat. Biasanya sinyal ini juga dikenal dengan sinyal diskret. Sinyal yang mempunyai dua keadaan ini biasa disebut dengan bit. Bit merupakan istilah khas pada sinyal digital. Sebuah bit dapat berupa nol (0) atau satu (1). Kemungkinan nilai untuk sebuah bit adalah 2 buah (21). Kemungkinan nilai untuk 2 bit adalah sebanyak 4 (22), berupa 00, 01, 10, dan 11. Secara umum, jumlah kemungkinan nilai yang terbentuk oleh kombinasi n bit adalah sebesar 2n buah. Teknologi digital memiliki beberapa keistimewaan unik yang tidak dapat ditemukan pada teknologi analog, yaitu :

Mampu mengirimkan informasi dengan kecepatan cahaya yang mengakibatkan informasi dapat dikirim dengan kecepatan tinggi.

Penggunaan yang berulang-ulang terhadap informasi tidak mempengaruhi kualitas dan kuantitas informasi itu sendiri.

Informasi dapat dengan mudah diproses dan dimodifikasi ke dalam berbagai bentuk.

Dapat memproses informasi dalam jumlah yang sangat besar dan mengirimkannya secara interaktif.

Pemahaman yang mudah tentang analog dan digital adalah pada pita kaset lagu dan file MP3. Jika meng-copy (menyalin) atau merekam pita kaset, tentu hasilnya banyak ditentukan oleh alat perekamnya, kebersihan ”head” rekam nya, dan sebagainya, semakin banyak merekam ke tempat lain, kualitas suaranya akan berubah. Tapi dengan meng-copy file MP3, akan mendapat salinannya sama persis dengan aslinya, berapapun banyaknya kamu menggandakannya.Kini ada juga yang menyalin lagu-lagu dari pita kaset menjadi file, atau disebut juga “men-digital-isasi”. Namun dalam bidang audio ini, sistem analog masih memiliki beberapa ”keunggulan” dibanding sistem digital, yang menyebabkan masih ada beberapa penggemar fanatik yang lebih menyukai rekaman analog.

Perbedaan kamera analog (manual) dan kamera digital hanya terletak pada media penyimpanannya, kalau kamera sebelumnya ”menyimpan” data gambar dalam bentuk film yang harus kamu proses dulu untuk bisa mendapatkan ”foto” nya, sementara kamrea digital menyimpan data gambarnya dalam bentuk data ”digital” yang bisa langsung kamu nikmati

sesaat setelah ”dijepret”.

Dalam bidang telekomunikasi, perbedaan telepon analog dan digital, bukan berdasarkan jenis pesawat teleponnya, namun kepada ”sistem” di sentral teleponnya, walaupun untuk mendukung sistem sentra yang digital, diperlukan pesawat telepon khusus. Begitu juga dengan siaran televisi analog dan digital. Siaran Analog kadang terganggu oleh cuaca, letak bangunan, dan penyebab lainnya, sementara siaran digital memiliki kualitas suara dan gambar yang lebih bagus, karena ”data”-nya tidak mengalami ”gangguan” saat dikirim ke TV penerima.

http://blog.ub.ac.id/cantikaordinary/2010/03/07/pengertian-dan-contoh-sistem-analog-dan-sistem-digital/

An analog or analogue signal is any continuous signal for which the time varying feature (variable)

of the signal is a representation of some other time varying quantity, i.e., analogous to another time

varying signal. For example, in an analogaudio signal, the instantaneous voltage of the signal varies

continuously with the pressure of the sound waves. It differs from a digital signal, in which a

continuous quantity is represented by a discrete function which can only take on one of a finite

number of values. The term analog signal usually refers to electrical signals;

however, mechanical, pneumatic, hydraulic, and other systems may also convey analog signals.

An analog signal uses some property of the medium to convey the signal's information. For example,

an aneroid barometeruses rotary position as the signal to convey pressure information. In an

electrical signal, the voltage, current, or frequency of the signal may be varied to represent the

information.

Any information may be conveyed by an analog signal; often such a signal is a measured response

to changes in physical phenomena, such as sound, light, temperature, position, or pressure. The

physical variable is converted to an analog signal by a transducer. For example, in sound recording,

fluctuations in air pressure (that is to say, sound) strike the diaphragm of a microphone which

induces corresponding fluctuations in the current produced by a coil in an electromagnetic

microphone, or the voltage produced by a condensor microphone. The voltage or the current is said

to be an "analog" of the sound.

An analog signal has a theoretically infinite resolution. In practice an analog signal is subject

to electronic noise anddistortion introduced by communication channels and signal

processing operations, which can progressively degrade thesignal-to-noise ratio. In contrast, digital

signals have a finite resolution. Converting an analog signal to digital form introduces a constant low-

level noise called quantization noise into the signal which determines the noise floor, but once in

digital form the signal can in general be processed or transmitted without introducing additional noise

or distortion. Therefore as analog signal processing systems become more complex, they may

ultimately degrade signal resolution to such an extent that their performance is surpassed by digital

systems. This explains the widespread use of digital signals in preference to analog in modern

technology. In analog systems, it is difficult to detect when such degradation occurs. However, in

digital systems, degradation can not only be detected but corrected as well.

Disadvantages[edit]

The primary disadvantage of analog signals is that any system has noise – i.e., random unwanted

variation. As the signal is copied and re-copied, or transmitted over long distances, or electronically

processed, the unavoidable noise introduced by each step in the signal path is additive,

progressively degrading the signal-to-noise ratio, until in extreme cases the signal can be

overwhelmed. This is called generation loss. Noise can show up as 'hiss' and intermodulation

distortion in audio signals, or "snow" in video signals. This degradation is impossible to recover,

since there is no sure way to distinguish the noise from the signal; amplifying the signal to recover

attenuated parts of the signal amplifies the noise (distortion/interference) as well. Digital signals can

be transmitted, stored and processed without introducing noise. Even if the resolution of an analog

signal is higher than a comparable digital signal, after enough processing the analog signal to noise

ratio will be lower.[citation needed]

Electrically, analog signal noise can be diminished by shielding, good connections, and several

cable types such as coaxialor twisted pair.

http://en.wikipedia.org/wiki/Analog_signal

Pengertian Sinyal Digital

Sinyal digital merupakan sinyal data dalam bentuk pulsa yang dapat mengalami perubahan yang tiba-tiba dan mempunyai besaran 0 dan 1. Teknologi Sinyal digital hanya memiliki dua keadaan, yaitu 0 dan 1, sehingga tidak mudah terpengaruh oleh derau/noise, tetapi transmisi dengan sinyal digital hanya mencapai jarak jangkau pengiriman data yang relatif dekat. Sinyal Digital juga biasanya disebut juga Sinyal Diskret.

Sistem Sinyal Digital merupakan bentuk sampling dari sytem analog. digital pada dasarnya di code-kan dalam bentuk biner (atau Hexa). besarnya nilai suatu system digital dibatasi oleh lebarnya / jumlah bit

(bandwidth). jumlah bit juga sangat mempengaruhi nilai akurasi system digital.

Teknologi Sinyal Digital ini juga memiliki kelebihan yang tidak dimiliki olehTeknologi Sinyal Analog. Diantaranya adalah dibawah ini :

 Mampu mengirimkan informasi dengan kecepatan cahaya yang dapat membuat informasi dapat

dikirim dengan kecepatan tinggi.

 Penggunaan yang berulang – ulang terhadap informasi tidak mempengaruhi kualitas dan

kuantitas informsi itu sendiri.

 Informasi dapat dengan mudah diproses dan dimodifikasi ke dalam berbagai bentuk.

Dapat memproses informasi dalam jumlah yang sangat besar dan mengirimnya secara interaktif.

Pada saat ini banyak teknologi-teknologi yang memakai Teknologi Sinyal Digital. Karena kelebihan kelebihannya, antara lain:

1. untuk menyimpan hasil pengolahan, sinyal digital lebih mudah dibandingkan sinyal analog. Untuk

menyimpan sinyal digital dapat menggunakan media digital seperti CD, DVD, Flash Disk,

Hardisk. Sedangkan media penyimpanan sinyal analog adalah pita tape magnetik.

2. lebih kebal terhadap noise karena bekerja pada level ’0′ dan ’1′.

3. lebih kebal terhadap perubahan temperatur.

4. lebih mudah pemrosesannya. 

A digital signal is a physical signal that is a representation of a sequence of discrete values

(a quantified discrete-time signal), for example of an arbitrary bit stream, or of

a digitized (sampled and analog-to-digital converted) analog signal. The term digital signal can refer

to either of the following:

1. any continuous-time waveform signal used in digital communication, representing a bit

stream or other sequence ofdiscrete values

2. a pulse train signal that switches between a discrete number of voltage levels or levels of

light intensity, also known as a line coded signal or baseband transmission, for example a

signal found in digital electronics or in serial communications, or a pulse code

modulation (PCM) representation of a digitized analog signal.

A signal that is generated by means of a digital modulation method (digital passband transmission),

to be transferred between modems, is in the first case considered as a digital signal, and in the

second case as converted to an analog signal.

In computer architecture and other digital systems, a waveform that switches between two voltage

levels representing the two states of aBoolean value (0 and 1) is referred to as a digital signal, even

though it is an analog voltage waveform, since it is interpreted in terms of only two levels.

The clock signal is a special digital signal that is used to synchronizedigital circuits. The image

shown can be considered the waveform of a clock signal. Logic changes are triggered either by the

rising edge or the falling edge.

The given diagram is an example of the practical pulse and therefore we have introduced two new

terms that are:

Rising edge: the transition from a low voltage (level 1 in the diagram) to a high voltage (level 2).

Falling edge: the transition from a high voltage to a low one.

Although in a highly simplified and idealised model of a digital circuit we may wish for these

transitions to occur instantaneously, no real world circuit is purely resistive and therefore no circuit

can instantly change voltage levels. This means that during a short, finite transition time the output

may not properly reflect the input, and indeed may not correspond to either a logically high or low

voltage.

Logic voltage levels[edit]

Hobbyist frequency counter circuit built almost entirely of TTL logic chips.

Main article:  logic level

The two states of a wire are usually represented by some measurement of an electrical

property: Voltage is the most common, but current is used in some logic families. A threshold is

designed for each logic family. When below that threshold, the wire is "low", when above "high."

Digital circuits establish a "no man's area" or "exclusion zone" that is wider than the tolerances of the

components. The circuits avoid that area, in order to avoid indeterminate results.

It is usual to allow some tolerance in the voltage levels used; for example, 0 to 2 volts might

represent logic 0, and 3 to 5 volts logic 1. A voltage of 2 to 3 volts would be invalid, and occur only in

a fault condition or during a logic level transition. However, few logic circuits can detect such a

condition and most devices will interpret the signal simply as high or low in an undefined or device-

specific manner. Some logic devices incorporate schmitt trigger inputs whose behaviour is much

better defined in the threshold region, and have increased resilience to small variations in the input

voltage.

The levels represent the binary integers or logic levels of 0 and 1. In active-high logic, "low"

represents binary 0 and "high" represents binary 1. Active-low logic uses the reverse representation.

http://en.wikipedia.org/wiki/Digital_signal