Lecture Slide 4

Low-Noise Amplifier (LNA)

The first active device in a receiver that reduces the noise of subsequent stages and amplifies the received signal.

Gain

The ratio of an amplifier's output power to its input power, usually measured in dB.

Isolation

The measure of transmission from the output to the input of an amplifier.

Return Loss

A measure of the quality of the match between the input and output of an amplifier, relative to the system impedance.

Impedance

The measure of the opposition to the flow of electric current in a circuit, both input and output.

SWR (Standing Wave Ratio)

A measure of the magnitude portion of the reflection coefficient.

Distortion

Undesirable extra tones at the output of an amplifier caused by the interaction of input signals.

P1dB (1 dB gain compression)

The input power level at which the amplifier's gain drops 1 dB relative to the small signal gain.

Noise Figure

A measure of the amount of noise added by an amplifier to the signal passing through it.

OIP3 (Third Order Intercept Point)

The input power level at which the third-order distortion products become equal in magnitude to the desired signal.

Group Delay

A measure of the transit time through an amplifier at a particular frequency.

3rd order product

The product generated in a system due to non-linearities, which increases by 3 dB for every 1 dB increase in input power.

Fundamental

The main input signal in a system, which has a slope of 1.

Input power (dBm)

The power level of the input signal, measured in decibels relative to 1 milliwatt.

Output power (dBm)

The power level of the output signal, measured in decibels relative to 1 milliwatt.

OIP3 (Third Order Intercept Point)

The input power level at which the third-order products intersect the fundamental with a slope of 3:1.

P1dB (1 dB Compression Point)

The input power level at which the output power is reduced by 1 dB due to compression in the system.

Gain

The amplification factor of a system.

OIP3 Calculation

The process of determining the OIP3 of an amplifier using measurements and formulas.

Spectrum Analyzer

A device used to measure and analyze the frequency spectrum of signals.

Extrapolated

Estimated or predicted based on existing data or measurements.

Compression

The reduction in dynamic range or linearity of a system due to high input power levels.

Lower level measure

Measurements taken at lower power levels.

TOI point

The Third Order Intercept point, which is the same as OIP3.

S

The signal power level.

D

The power difference between the output and input signals.

Loss at output

The power loss at the output of the system.

LPF (Low Pass Filter)

A filter that allows low-frequency signals to pass through while attenuating high-frequency signals.

Attenuator

A device used to reduce the power level of a signal.

Isolator

A device used to prevent unwanted interactions or reflections between components.

DUT (Device Under Test)

The component or device being tested.

Matching

The process of optimizing the impedance match between components to minimize reflections and maximize power transfer.

Dynamic range

The range of signal power levels that a system can accurately measure or process.

Quality of the test equipment

The performance and accuracy of the test equipment used.

3rd order products

The unwanted products generated in a system due to non-linearities, which increase by 3 dB for every 1 dB increase in input power.

Error

Deviation or inaccuracy in measurements or calculations.

Noise

Undesirable signals that are present along with the desired signal.

Bandwidth

The range of frequencies over which a system can operate or a signal can be transmitted.

External Noise

Noise that originates from sources outside of the system, such as interference or cross-talk.

Interference

Unwanted signals that disrupt or distort the desired signal.

Internal Noise

Noise that is generated by the internal components of a system.

Shot Noise

Noise that is due to the flow of current across a potential barrier in a PN junction.

Flicker Noise

Noise that is significant at audio frequencies and has an amplitude inversely proportional to frequency.

Thermal Noise

Noise that arises from the random motion of electrons due to heat.

VT

Thermal voltage, which is equal to 0.5 times the product of Boltzmann's constant and temperature.

R1

Resistance of the source.

R2

Resistance at the output.

V

Voltage across the resistance.

Max Available Noise Power

The maximum power of the noise that can be transferred to the load.

PN

Noise power.

k

Boltzmann's constant.

T

Temperature.

R

Resistance.

Noise Figure

A measure of the noise added by a device, quantifying the degradation in signal-to-noise ratio (SNR) in dB.

ENR

Excess Noise Ratio, a parameter used in noise figure measurements.

Y-Factor Method

A method used to measure noise figure using an Excess Noise Ratio (ENR) source.

Cold Source Method

A method used to measure noise figure using a vector network analyzer with a built-in noise figure receiver.

Vector Network Analyzer

A device used to measure the complex impedance and transmission characteristics of electrical networks.

ENR Table

A table that provides the ENR values for a noise source at specified frequencies.

Direct Source Method

Another term for the Cold Source Method.

Personality Software Option

Software that enables specific functions or capabilities in a spectrum analyzer.

Spurious Signals

Unwanted signals that appear in the frequency spectrum.

Sensitivity

The ability of a device to detect weak signals.

Noise Figure Meter/Analyzer

A device used to measure the noise figure of a system or component.

IF Path

Intermediate Frequency path, the signal path in a receiver after the initial frequency conversion.

Noise Source

A device that generates noise for noise figure measurements.

LNA

Low-Noise Amplifier, a device used to amplify weak signals with minimal noise contribution.

Faraday Cage

An enclosure made of conductive material that blocks external electromagnetic fields.

F1

Noise figure of the DUT (Device Under Test).

G1

Gain of the DUT.

F2

Noise figure measured by the instrument.

Fsys

System noise figure.

Y

Y-factor, the ratio of the noise powers with the noise source on and off.

Te

Noise temperature of the DUT.

Calibrate

The process of adjusting or setting the measurement instrument to a known reference or standard.

Gain

The amplification factor of a system or component.

Fsys

System noise figure, the noise figure of the entire system including the DUT.

2-stage NF

A noise figure measurement setup with two stages, typically consisting of a noise source, DUT, and noise figure instrument.

Noise Figure

The degradation in signal-to-noise ratio (SNR) in decibels (dB) as signal and noise pass through a device under test (DUT).

Attenuator

A device used to reduce the power or amplitude of a signal.

Thermal noise

The random noise generated by the thermal agitation of electrons in a conductor.

Signal-to-Noise Ratio (SNR)

The ratio of the power of a signal to the power of the background noise.

LNA (Low-Noise Amplifier)

The first active device in a receiver, designed to amplify weak signals while introducing minimal noise.

NF (Noise Figure) Meter/Analyzer

A device used to measure the noise figure of a device or system.