Signal

/ˈdɪdʒɪtl ˈsɪgnəl ˈprəʊsɛsɪŋ/

noun — "analyzing and modifying signals with algorithms."

Digital Signal Processing, often abbreviated as DSP, is the mathematical and computational manipulation of digital signals to extract information, improve quality, or enable desired transformations. It involves the use of algorithms to process sampled data from analog signals that have been converted to digital form via an analog-to-digital converter (ADC). DSP is fundamental in telecommunications, audio and video processing, biomedical instrumentation, radar systems, and embedded electronics.

Technically, DSP algorithms operate on discrete-time signals, performing operations such as filtering, Fourier transforms, convolution, correlation, modulation, and compression. Systems implementing DSP can be realized in software on general-purpose processors, in specialized DSP processors, or in hardware using FPGAs and ASICs for high-speed applications. Precision, sampling rate, and computational efficiency are key considerations, as these factors affect signal fidelity and system performance.

# Example: simple digital low-pass filter (conceptual)
input_signal = [x0, x1, x2, x3, ...]
output_signal[0] = input_signal[0]
for n in 1..N:
    output_signal[n] = 0.5 * input_signal[n] + 0.5 * output_signal[n-1]
# applies smoothing to high-frequency variations

In embedded workflows, DSP is used to:

• Enhance audio signals in speakers or headphones
• Filter noise from sensor measurements
• Compress video streams for transmission
• Detect patterns in radar or medical imaging signals

Conceptually, DSP is like a digital craftsman shaping and refining signals. Raw measurements are transformed into cleaner, more usable, or more meaningful forms by applying mathematical tools and algorithms. Whether isolating a voice from background noise, compressing a video without losing detail, or detecting a heartbeat pattern, DSP makes precise, reliable signal manipulation possible in digital systems.

See FPGA, ASIC, Embedded Systems, ADC, Filter.

/ˌpiːˌdʌbəljuːˈɛm/

noun — "modulates digital signal duty to control analog behavior."

PWM, short for Pulse-Width Modulation, is a technique used to encode analog signal levels or control power delivered to electronic devices by varying the duty cycle of a digital square wave. It allows a digital output, such as a microcontroller pin, to simulate analog voltage levels by controlling the ratio of time the signal is high versus low within a fixed period.

Technically, a PWM signal is defined by two main parameters:

• Frequency — the number of complete cycles per second
• Duty cycle — the percentage of one cycle in which the signal is high

The output voltage seen by a device is proportional to the duty cycle. For example, a 50% duty cycle on a 5V signal results in an average voltage of 2.5V over the cycle.

# Example: controlling LED brightness
PWM_frequency = 1000  # 1 kHz
Duty_cycle = 75      # 75 high, 25 low
# LED sees an average of 0.75 * 5V = 3.75 V

In embedded systems, PWM is commonly used for:

• Controlling LED brightness
• Driving motors with variable speed
• Generating audio tones or simple waveforms
• Voltage regulation in power electronics

The microcontroller or peripheral hardware generates the PWM signal using timers or counters. Software configures the frequency, duty cycle, and output pin, while the hardware ensures precise timing. Some advanced PWM modules support complementary outputs, dead-time insertion, and synchronized multi-channel operation for complex motor control.

Conceptually, PWM is like turning a switch on and off very quickly. The longer the switch is on relative to off, the brighter the LED or faster the motor spins. The device integrates the high-speed pulses into an effective analog response, giving precise control while using simple digital logic.

See GPIO, Microcontroller, Embedded Systems, SPI.

/ˈkʌrənt/

noun … “Flow of electric charge.”

Current is the rate at which electric charge flows through a conductor or circuit, typically carried by electrons in metals or ions in electrolytes. It is one of the fundamental concepts in electricity, working alongside voltage and resistance to describe how electrical energy moves and performs work in circuits.

Key characteristics of Current include:

• Unit: measured in amperes (A), representing one coulomb of charge per second.
• Direction: conventional current flows from positive to negative, opposite to electron flow.
• Types: Alternating current (AC) reverses direction periodically; Direct current (DC) flows in one direction.
• Relationship to voltage and resistance: governed by Ohm’s law, I = V / R.
• Effects: produces magnetic fields, generates heat, and enables work to be done in electrical devices.

Applications of Current include powering electronic devices, motors, lighting, heating elements, and communication systems.

Workflow example: Calculating current through a resistor:

voltage = 9       -- Volts
resistor = 1000    -- Ohms
current = voltage / resistor
print(current)     -- 0.009 A (9 mA)

Here, current is determined by the applied voltage and resistance, flowing through the circuit to perform work.

Conceptually, Current is like the flow of water through a pipe: the amount of water passing a point per unit time corresponds to electric current.

See Voltage, Resistance, Power, AC, DC.

/ˈvoʊltɪdʒ/

noun … “Electrical potential difference between two points.”

Voltage is the measure of electric potential energy per unit charge between two points in a circuit. It represents the force that drives electric charges to move through a conductor, creating current. Voltage is fundamental to understanding and designing electrical and electronic systems.

Key characteristics of Voltage include:

• Unit: measured in volts (V).
• Polarity: has positive and negative terminals indicating direction of potential difference.
• Source types: can be supplied by batteries, generators, solar cells, or power supplies.
• AC vs DC: can alternate in direction (AC) or remain constant (DC).
• Relation to energy: energy delivered to a charge is the product of voltage and charge (E = V × Q).

Applications of Voltage include powering circuits, driving motors, charging batteries, and controlling electronic devices. Understanding voltage is essential for calculating current, resistance, and power in circuits.

Workflow example: Calculating current using Ohm's law:

resistor = 1000   -- Ohms
voltage = 5       -- Volts
current = voltage / resistor
print(current)    -- 0.005 A

Here, voltage drives current through the resistor according to Ohm’s law.

Conceptually, Voltage is like water pressure in a pipe: it determines how strongly charges (or water) are pushed through the system.

See Current, Resistance, Power, AC, DC.

/ɪˌlɛkˈtrɪsɪti/

noun … “Flow of electric charge.”

Electricity is the phenomenon resulting from the presence and flow of electric charges, typically electrons, through a medium. It manifests as current (current), voltage (voltage), and electromagnetic fields, and it powers almost all modern devices, from lights and motors to computers and communication systems. Electricity can be harnessed in alternating current (AC) or direct current forms.

Key characteristics of Electricity include:

• Current: flow of charge, measured in amperes (A).
• Voltage: potential difference driving the flow, measured in volts (V).
• Resistance: opposition to current flow, measured in ohms (Ω).
• Power: energy delivered per unit time, measured in watts (W).
• Frequency: number of cycles per second in AC, measured in hertz (Hz).

Common applications of Electricity include powering electronics, heating, lighting, transportation, industrial machinery, and telecommunications. Understanding electricity is essential for designing circuits, energy systems, and electronic devices.

Workflow example: Simple circuit powering a light:

battery_voltage = 9
resistor = 1000
current = battery_voltage / resistor
light.power(current)

Here, electricity flows from the battery through the resistor to the light, producing illumination according to Ohm's law.

Conceptually, Electricity is like a river of tiny charges flowing through a conductive path, delivering energy wherever it travels.

See Current, Voltage, Power, AC, DC.

/ˌeɪ ˈsiː/

noun … “Electric current that periodically reverses direction.”

AC, short for Alternating Current, is a type of electrical current in which the flow of electric charge reverses direction periodically, typically in a sinusoidal waveform. AC is the standard form of electricity delivered by power grids because it can be easily transformed to different voltages for efficient long-distance transmission.

Unlike DC, which flows in a single direction, AC continuously changes polarity and magnitude, allowing devices such as transformers to step voltage up or down without significant energy loss. AC is widely used to power homes, industrial equipment, and most household appliances.

Key characteristics of AC include:

• Periodic reversal: current alternates direction at a fixed frequency (e.g., 50 or 60 Hz).
• Variable amplitude: voltage and current vary continuously over time.
• Efficient transmission: high-voltage AC reduces energy loss over long distances.
• Conversion capability: AC can be converted to DC using rectifiers.
• Standardization: widely used for power grids worldwide.

Workflow example: AC powering a household device:

ac_wall_voltage = 120   -- volts, typical in North America
device_input = transformer.step_down(ac_wall_voltage, 12)
device.power(device_input)

Here, AC voltage from the wall is stepped down and conditioned to safely power an electronic device.

Conceptually, AC is like water sloshing back and forth in a pipe, constantly changing direction but delivering energy to a turbine or generator efficiently.

See DC, Transformer, Rectifier, Power Supply, Electricity.

/ˌdiː ˈsiː/

noun … “Electric current that flows in one direction.”

DC, short for Direct Current, is a type of electrical current in which electric charge flows consistently in a single direction. Unlike alternating current, where the direction of flow periodically reverses, DC maintains constant polarity, making it especially suitable for electronic circuits, digital systems, and energy storage.

DC is the natural form of electricity produced by sources such as batteries, solar cells, and fuel cells. Inside electronic devices, even those powered from AC wall outlets, electricity is almost always converted to DC using a rectifier and stabilized with a voltage regulator.

Key characteristics of DC include:

• Unidirectional flow: current moves in only one direction.
• Constant polarity: voltage does not alternate sign.
• Stable voltage levels: ideal for logic and control circuits.
• Energy storage compatibility: easily stored in batteries and capacitors.
• Low noise: preferred for sensitive electronic components.

Common uses of DC include powering microcontrollers, CPUs, memory, sensors, motors (with control electronics), and communication devices.

Workflow example: Supplying DC to a circuit:

battery_voltage = 9
regulated_voltage = voltage_regulator.set(5).apply(battery_voltage)
circuit.power(regulated_voltage)

Here, DC from a battery is regulated to a lower, stable voltage suitable for digital electronics.

Conceptually, DC is like water flowing steadily through a pipe in one direction, without reversing or pulsing back and forth.

See AC, Power Supply, Rectifier, Voltage Regulator, Battery.

/ˈrɛktɪfaɪər/

noun … “Circuit that converts alternating current to direct current.”

Rectifier is an electronic circuit or device that converts alternating current (AC) into direct current (DC). Rectification is a fundamental process in power electronics, allowing electrical systems and devices that require steady, one-directional current to operate using AC power sources such as wall outlets or generators. Rectifiers are built primarily using diodes, which enforce one-way current flow.

In operation, a Rectifier blocks portions of the AC waveform that flow in the undesired direction and passes the portions that flow in the desired direction. The resulting output is a pulsating DC signal, which is often smoothed using capacitors, inductors, or voltage regulators to produce a more stable DC supply.

Key characteristics of Rectifier include:

• Direction control: converts bidirectional AC into unidirectional DC.
• Diode-based design: relies on diode forward and reverse bias behavior.
• Efficiency considerations: affected by diode voltage drops and power dissipation.
• Ripple: residual AC variation present in rectified output.
• Scalability: used in low-power signal circuits and high-power industrial systems.

Common types of Rectifier include half-wave rectifiers, full-wave rectifiers, and bridge rectifiers. Full-wave and bridge designs are preferred in most power supplies because they utilize both halves of the AC waveform and produce smoother DC output.

Workflow example: Full-wave bridge rectification:

ac_input = alternating_voltage()
positive_half = abs(ac_input)
dc_output = positive_half

Here, the rectifier inverts negative portions of the AC waveform so that current always flows in the same direction.

Conceptually, a Rectifier is like a traffic system that redirects cars so they all travel in the same direction, regardless of where they started.

See Diode, Power Supply, AC, DC, Voltage Regulator.

/ˈæmplɪfaɪər/

noun … “Device that increases signal strength.”

Amplifier is an electronic circuit or device that increases the amplitude of a signal, making it stronger in voltage, current, or power without altering the underlying information it carries. Amplifiers are essential in both analog and digital systems, enabling weak signals from sensors, microphones, or antennas to be processed, transmitted, or reproduced effectively.

Key characteristics of Amplifier include:

• Gain: the ratio of output signal strength to input signal strength.
• Linearity: ability to amplify without introducing distortion.
• Bandwidth: range of frequencies the amplifier can handle effectively.
• Noise performance: amount of unwanted signal added during amplification.
• Efficiency: how effectively electrical power is converted into amplified output.

Workflow example: Audio signal amplification:

microphone_signal = mic.read()
amplified_signal = amplifier.gain(20).apply(microphone_signal)
speaker.play(amplified_signal)

Here, a weak microphone signal is amplified so it can drive a speaker, preserving the original sound while increasing its strength.

Conceptually, an Amplifier is like a megaphone: it takes a quiet voice and makes it louder without changing the words being spoken.

See Transistor, Semiconductor, Signal Processing, Gain, Analog.

/ˈbaɪnəri/

adjective … “Based on two discrete values, 0 and 1.”

Binary refers to a number system, representation, or data encoding that uses only two symbols, typically 0 and 1. In computing, binary underlies all digital systems, as digital signals, memory storage, and logic circuits operate on two-state systems. Binary representation enables efficient computation, storage, and communication of information using simple, reliable hardware components.

Key characteristics of Binary include:

• Two-state system: values are either 0 (off/false) or 1 (on/true).
• Foundation of digital logic: used in logic gates, flip-flops, and CPUs.
• Ease of processing: simple arithmetic and bitwise operations are supported natively.
• Representation of complex data: sequences of binary digits (bits) encode numbers, characters, images, and instructions.
• Compatibility: binary data can be transmitted, stored, and processed reliably in electronic systems.

Workflow example: Binary addition:

0b1010 + 0b0111 = 0b10001
-- 1010 (10 decimal) + 0111 (7 decimal) = 10001 (17 decimal)

Here, numbers are represented in binary and arithmetic is performed at the bit level, as in all digital computation.

Conceptually, Binary is like a series of light switches: each switch is either off or on, and combinations of switches encode information or control systems.

See Digital, Logic Gates, Bit, CPU, Memory.