The aim of pulse modulation methods is to transfer a narrowband analog signal, for example a phone call over a wideband baseband channel or, in some of the schemes, as a bit stream over another digital transmission system.

The term digital baseband modulation ( or digital baseband transmission ) is synonymous to line codes.

Digital baseband transmission, also known as line coding, aims at transferring a digital bit stream over baseband channel, typically an unfiltered wire, contrary to passband transmission, also known as carrier-modulated transmission.

The word " BASE " in Ethernet physical layer standards, for example 10BASE5, 100BASE-T and 1000BASE-SX, implies baseband digital transmission, i. e. that a line code and an unfiltered wire are used.

A baseband processor is a chip in wireless transmission devices such as mobile phones, that performs signal processing and implements the device's realtime radio transmission operations.

For example, a switched analog connection in the telephone network has energy below 300 Hz and above 3400 Hz removed by bandpass filtering ; since the signal has no energy very close to zero frequency, it may not be considered a baseband signal, but in the telephone systems frequency-division multiplexing hierarchy, it is usually treated as a baseband signal, by comparison with the modulated signals used for long-distance transmission.

It is caused by unwanted modulation products which arise from the transmission of the carrier signal, and appear in the form of a rectified baseband that interferes with the lower sideband of the carrier.

In telecommunication, a line code ( also called digital baseband modulation, also called digital baseband transmission method ) is a code chosen for use within a communications system for baseband transmission purposes.

There are two main categories of digital communication transmission methods: baseband and passband.

The messages are either represented by a sequence of pulses by means of a line code ( baseband transmission ), or by a limited set of continuously varying wave forms ( passband transmission ), using a digital modulation method.

For example, a 3 kHz band can carry a telephone conversation whether that band is at baseband ( as in your POTS telephone line ) or modulated to some higher frequency.

The aim of digital baseband modulation methods, also known as line coding, is to transfer a digital bit stream over a baseband channel, typically a non-filtered copper wire such as a serial bus or a wired local area network.

# as an upper bound for the symbol rate across a bandwidth-limited baseband channel such as a telegraph line or passband channel such as a limited radio frequency band or a frequency division multiplex channel.

# A baseband signal (" digital-over-digital " transmission ): A sequence of electrical pulses or light pulses produced by means of a line coding scheme such as Manchester coding.

The word broadband as used in the original IEEE 802. 3 specifications implied operation in frequency-division multiplexed ( FDM ) channel bands as opposed to digital baseband square-waveform modulations ( also known as line coding ), which begin near zero Hz and theoretically consume infinite frequency bandwidth.

Many computer networks use a simple line code to transmit one type of signal using a medium's full bandwidth using its baseband ( from zero through the highest frequency needed ).

The original Ethernet standard 10BASE-T used a baseband encoding ( also known as line coding ), where the signal is simply encoded directly on the wire without any sort of carrier wave.

More specifically, a line code ( or baseband transmission scheme ) representing the data using pulse-amplitude modulation with 2 < sup > N </ sup > different voltage levels, can transfer N bit / pulse.

In the case of baseband transmission ( line coding or pulse-amplitude modulation ) with a baseband bandwidth ( or upper cut-off frequency ) B, the symbol rate can not exceed 2B symbols / s in view to avoid intersymbol interference.

In case of a baseband channel such as a telegraph line, a serial cable or a Local Area Network twisted pair cable, data is transferred using line codes, i. e. pulses rather than sinewave tones.

The modulation system was based on that used in a Swedish paging system and the baseband coding was a new design, mainly developed by the British Broadcasting Corporation ( BBC ) and the IRT.

It is typically measured in hertz, and may sometimes refer to passband bandwidth, sometimes to baseband bandwidth, depending on context.

In case of a low-pass filter or baseband signal, the bandwidth is equal to its upper cutoff frequency.

The fact that in equivalent baseband models of communication systems, the signal spectrum consists of both negative and positive frequencies, can lead to confusion about bandwidth, since they are sometimes referred to only by the positive half, and one will occasionally see expressions such as, where is the total bandwidth ( i. e. the maximum passband bandwidth of the carrier-modulated RF signal and the minimum passband bandwidth of the physical passband channel ), and is the positive bandwidth ( the baseband bandwidth of the equivalent channel model ).

At the subscriber's residence, either the subscriber's television or a set-top box provided by the cable company translates the desired channel back to its original frequency ( baseband ), and it is displayed on the screen.

If the baseband data signal ( the message ) to be transmitted is and the sinusoidal carrier is, where f < sub > c </ sub > is the carrier's base frequency and A < sub > c </ sub > is the carrier's amplitude, the modulator combines the carrier with the baseband data signal to get the transmitted signal:

Modulation of a sine waveform is used to transform a baseband message signal into a passband signal, for example low-frequency audio signal into a radio-frequency signal ( RF signal ).

The aim of analog modulation is to transfer an analog baseband ( or lowpass ) signal, for example an audio signal or TV signal, over an analog bandpass channel at a different frequency, for example over a limited radio frequency band or a cable TV network channel.

The resulting so called equivalent lowpass signal or equivalent baseband signal is a complex-valued representation of the real-valued modulated physical signal ( the so-called passband signal or RF signal ).

* For small amplitude signals, PM is similar to amplitude modulation ( AM ) and exhibits its unfortunate doubling of baseband bandwidth and poor efficiency.

The earliest magnetic recording systems simply applied the unadulterated ( baseband ) input signal to a recording head, resulting in recordings with poor low-frequency response and high distortion.

The model can be a linear or non-linear, time-continuous or time-discrete ( sampled ), memoryless or dynamic ( resulting in burst errors ), time-invariant or time-variant ( also resulting in burst errors ), baseband, passband ( RF signal model ), real-valued or complex-valued signal model.

If the player is not capable of using the side information that has been transmitted alongside the " normal " compressed audio data, it may still be able to play the " baseband " data as usual, resulting in a dull ( since the high frequencies are missing ), but otherwise mostly acceptable sound.

If digital single-sideband modulation is used, the passband signal with bandwidth W corresponds to a baseband message signal with baseband bandwidth W, resulting in a maximum symbol rate of 2W and an attainable modulation efficiency of 2N ( bit / s )/ Hz.

These are methods to transfer a digital bit stream over an analog baseband channel ( a. k. a. lowpass channel ) using a pulse train, i. e. a discrete number of signal levels, by directly modulating the voltage or current on a cable.

Pulse modulation schemes aim at transferring a narrowband analog signal over an analog baseband channel as a two-level signal by modulating a pulse wave.

* the line-coded signal ( the " baseband signal ") undergoes further pulse shaping ( to reduce its frequency bandwidth ) and then modulated ( to shift its frequency ) to create an " RF signal " that can be sent through free space.

It may also include analog-over-analog pulse modulatated baseband signals such as pulse-width modulation.

For a given complex baseband pulse, the narrowband ambiguity function is given by

A GFSK modulator, is similar to a FSK modulator, except that before the baseband pulses (− 1, + 1 ) go into the FSK modulator, it is passed through a gaussian filter to make the pulse smoother so to limit its spectral width.

A symbol can be described as either a pulse ( in digital baseband transmission ) or a " tone " ( in passband transmission using modems ) representing an integer number of bits.