Sampling | Teleinf Edu
The first step of A/D conversion: the Nyquist-Shannon sampling theorem.
2 min
Signal Processing
Coding, conversion, modulation, multiplexing, and error-control fundamentals for telecom signals.
Articles: 61
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Quantization | Teleinf Edu
Converting continuous sample amplitudes into discrete levels and the resulting quantization noise.
2 min
Companding | Teleinf Edu
Nonlinear quantization using A-law and µ-law to improve SQNR for low-amplitude signals.
2 min
Pulse Code Modulation (PCM) | Teleinf Edu
A method for representing analog signals in digital form, including voice.
2 min
Delta Modulation (DM) | Teleinf Edu
A simple 1-bit differential coding technique, including its adaptive variants (ADM).
2 min
Differential PCM (DPCM/ADPCM) | Teleinf Edu
DPCM and ADPCM differential coding with multibit quantization.
2 min
A/D Converter Methods | Teleinf Edu
An overview of indirect (e.g., integrating) and direct (e.g., flash) conversion techniques.
2 min
Flash A/D Converters | Teleinf Edu
A parallel ADC architecture with simultaneously operating comparators.
2 min
Integrating A/D Converters | Teleinf Edu
A/D conversion using single-slope and dual-slope integration.
2 min
Successive Approximation ADC | Teleinf Edu
A widely used method balancing speed and resolution via iterative comparisons.
2 min
Weighted Resistor D/A Converters | Teleinf Edu
Converting digital words to analog signals using a weighted resistor network.
2 min
R-2R Ladder D/A Converters | Teleinf Edu
A precise and practical DAC architecture using a ladder of only two resistor values.
2 min
Line Coding | Teleinf Edu
Mapping binary data to physical signals for transmission (NRZ, RZ, Manchester, AMI, HDB3).
2 min
Scrambling (Randomization) | Teleinf Edu
Using pseudo-random sequences (PRBS) to support clock recovery and limit the DC component.
2 min
Clock Recovery - Technical Implementation | Teleinf Edu
Advanced clock recovery techniques including PLL architectures, jitter performance, and implementation considerations.
2 min
Frame Synchronization | Teleinf Edu
Techniques for locating frame boundaries and validating frame alignment in a received data stream.
2 min
NRZ Codes | Teleinf Edu
The basics of Non-Return-to-Zero line coding and its spectral properties.
2 min
RZ Codes | Teleinf Edu
The principles of Return-to-Zero codes and their effect on clock recovery.
2 min
Manchester Code | Teleinf Edu
A self-clocking line code used in Ethernet with built-in transitions.
2 min
AMI Code | Teleinf Edu
Alternate Mark Inversion: a bipolar code that eliminates DC component.
2 min
HDB3 Code | Teleinf Edu
High-Density Bipolar 3-zero code, an enhancement of AMI that avoids long zero sequences.
2 min
CMI Code | Teleinf Edu
Coded Mark Inversion, a line code that provides transitions for clock recovery.
2 min
Block Codes (mB/nB) | Teleinf Edu
Redundant codes like 1b/2b or 3b/4b used in fiber optics to ensure DC balance and synchronization.
2 min
Introduction to Error Control | Teleinf Edu
Concepts of redundancy, ARQ (feedback) and FEC (forward error correction).
2 min
Parity Check | Teleinf Edu
A simple error detection method based on counting the number of ones.
2 min
Repetition Codes | Teleinf Edu
The simplest form of FEC based on majority voting.
2 min
Hamming Code | Teleinf Edu
A classic single-error correcting, double-error detecting block code.
2 min
Cyclic Redundancy Check (CRC) | Teleinf Edu
An error-detection technique based on polynomial division.
2 min
What is Modulation? | Teleinf Edu
Moving an information signal to a selected passband with a carrier wave.
2 min
Amplitude Modulation (AM) | Teleinf Edu
Amplitude modulation of a carrier wave, including DSB-WC, DSB-SC, and SSB variants.
2 min
Frequency Modulation (FM) | Teleinf Edu
Varying the frequency of the carrier. Concepts of deviation and modulation index.
2 min
Phase Modulation (PM) | Teleinf Edu
Varying the phase of the carrier wave and its relationship with FM.
2 min
Amplitude-Shift Keying (ASK) | Teleinf Edu
Digital modulation by switching between discrete amplitude levels.
2 min
Frequency-Shift Keying (FSK) | Teleinf Edu
Digital modulation by switching between discrete frequency levels.
2 min
Phase-Shift Keying (PSK) | Teleinf Edu
The general principle of digital modulation by shifting the phase of the carrier.
2 min
Constellation Diagrams | Teleinf Edu
Visualizing digital modulation schemes in the I-Q plane.
2 min
Binary Phase-Shift Keying (BPSK) | Teleinf Edu
The simplest form of PSK, using two phases to encode 1 bit per symbol.
2 min
Quadrature Phase-Shift Keying (QPSK) | Teleinf Edu
Using four phases to encode 2 bits per symbol, doubling the data rate of BPSK.
2 min
Offset QPSK (OQPSK) | Teleinf Edu
A QPSK variant that limits direct phase reversals and reduces envelope variation after pulse shaping.
2 min
Differential PSK (DPSK) | Teleinf Edu
Encoding information in the phase difference between symbols to simplify receivers.
2 min
Dual-Polarization QPSK (DP-QPSK) | Teleinf Edu
Doubling spectral efficiency by transmitting two independent QPSK signals on orthogonal polarizations.
2 min
M-ary Phase-Shift Keying (M-PSK) | Teleinf Edu
Generalizing PSK to M phases; when M=2^N, each symbol carries log2(M) bits.
2 min
MSK and GMSK | Teleinf Edu
Continuous-phase FSK schemes, including Minimum Shift Keying.
2 min
Quadrature Amplitude Modulation (QAM) | Teleinf Edu
Combining ASK and PSK for high spectral efficiency (16-QAM, 64-QAM).
2 min
Pulse Amplitude Modulation (PAM) | Teleinf Edu
Modulating the amplitude of a pulse train, a key step in sampling.
2 min
Pulse Width Modulation (PWM) | Teleinf Edu
Encoding information in the duration (width) of pulses.
2 min
Pulse Position Modulation (PPM) | Teleinf Edu
Encoding information in the time position of pulses.
2 min
Pulse Density Modulation (PDM) | Teleinf Edu
Representing an analog signal's amplitude via the density of pulses.
2 min
Transmission Speed Dependence on Modulation | Teleinf Edu
Analysis of R_b = R_s * m relationship and impact of modulation complexity on spectral efficiency.
2 min
Frequency-Division Multiplexing (FDM) | Teleinf Edu
Multiplexing technique that divides the available bandwidth into separate frequency bands for different signals.
2 min
Time-Division Multiplexing (TDM) | Teleinf Edu
Multiplexing technique that divides transmission time into separate time slots for different signals.
2 min
Code-Division Multiple Access (CDMA) | Teleinf Edu
Multiple access technique using spread spectrum and unique codes for each user.
2 min
Space-Division Multiplexing (SDM) | Teleinf Edu
Multiplexing technique that uses spatial separation or multiple antennas to transmit multiple signals simultaneously.
2 min
Mode-Division Multiplexing (MDM) | Teleinf Edu
Multiplexing technique that sends independent signals through distinct propagation modes in one waveguide or optical fiber.
2 min
Wavelength-Division Multiplexing (WDM) | Teleinf Edu
Optical multiplexing technique that uses different wavelengths of light to carry separate signals.
2 min
Wavelength-Division Multiplexing (WDM) | Teleinf Edu
Optical multiplexing technique that uses different wavelengths of light to carry separate signals.
2 min
Dense Wavelength-Division Multiplexing (DWDM) | Teleinf Edu
DWDM optical multiplexing with closely spaced wavelength channels for high-throughput transmission.
2 min
Optical Time-Division Multiplexing (OTDM) | Teleinf Edu
High-speed optical multiplexing technique that interleaves optical pulses in time domain.
2 min
Orthogonal Frequency-Division Multiplexing (OFDM) | Teleinf Edu
Principles of multi-carrier transmission with orthogonal subcarriers for high spectral efficiency.
2 min
Orthogonal Frequency-Division Multiple Access (OFDMA) | Teleinf Edu
Multiple access scheme based on OFDM that allocates subcarriers to different users.
2 min
Multiple-Input Multiple-Output (MIMO) | Teleinf Edu
Antenna technology using multiple transmit and receive antennas to improve communication performance.
2 min