https://download.tek.com/document/37W_17249_6_Fundamentals_of_Real-Time_Spectrum_Analysis1.pdf
GLOSSARY
| Acquisition | An integer number of time-contiguous samples. |
| Acquisition Time | The length of time represented by one acquisition |
| Amplitude | The magnitude of an electrical signal. |
| Amplitude Modulation (AM) | The process in which the amplitude of a sine wave (the carrier) is varie in accordance with the instantaneous voltage of a second electrical signal (the modulating signal). |
| Analysis Time | A subset of time-contiguous samples from one block, used as input to an analysis view. |
| Analysis View | The fexible window used to display real-time measurement results. |
| Carrier | The RF signal upon which modulation resides. |
| Carrier Frequency | The frequency of the CW component of the carrier signal. |
| Center Frequency | The frequency corresponding to the center of a frequency span of a spectrum the analyzer display. |
| CZT-Chirp-Z transform | A computationally effcient method of computing a Discrete Fourier Transform (DFT). CZTs offer more fexibility for example in selecting the number of output frequency points than the conventional FFT at the expense of additional computations. |
| CW Signal | Continuous wave signal. A sine wave. |
| dBfs | A unit to express power level in decibels referenced to full scale. Depending on the context, this is either the full scale of the display screen or the full scale of the ADC. |
| dBm | A unit to express power level in decibels referenced to 1 milliwatt. |
| dBmV | A unit to express voltage levels in decibels referenced to 1 millivolt. |
| Decibel (dB) | Ten times the logarithm of the ratio of one electrical power to another. |
| Discrete Fourier transform | A mathematical process to calculate the frequency spectrum of a sampled time domain signal. |
| Display Line | A horizontal or vertical line on a waveform display, used as a reference for visual (or automatic) comparison with a given level, time, or frequency. |
| Distortion | Degradation of a signal, often a result of nonlinear operations, resulting in unwanted frequency components. Harmonic and intermodulation distortions are common types. |
| DPX | Digital Phosphor analysis - A signal analysis and compression methodology that allows the live view of timechanging signals allowing the discovery of rare transient events. |
| DPX Spectrum | DPX technology applied to spectrum analysis. DPX Spectrum provides a Live RF view as well as the observation frequency domain transients. |
| Dynamic Range | The maximum ratio of the levels of two signals simultaneously present at the input which can be measured to a specifed accuracy. |
| Fast Fourier Transform | A computationally effcient method of computing a Discrete Fourier Transform (DFT). A common FFT algorithm requires that the number of input and output samples are equal and a power of 2 (2,4,8,16,…). |
| Frequency | The rate at which a signal oscillates, expressed as hertz or number of cycles per second. |
| Frequency Domain View | The representation of the power of the spectral components of a signal as a function of frequency; the spectrum of the signal. |
| Frequency Drift | Gradual shift or change a signal frequency over the specifed time, where other conditions remain constant. Expressed in hertz per second. |
| Frequency Mask Trigger | A fexible real-time trigger based on specifc events that occur in the frequency domain. The triggering parameters are defned by a graphical mask. |
| Frequency Modulation (FM) | The process in which the frequency of an electrical signal (the carrier) is varied according to the instantaneous voltage of a second electrical signal (the modulating signal). |
| Frequency Range | The range of frequencies over which a device operates, with lower and upper bounds. |
| Frequency Span | A continuous range of frequencies extending between two frequency limits. |
| Marker | A visually identifable point on a waveform trace, used to extract a readout of domain and range values represented by that point. |
| Modulate | To vary a characteristic of a signal, typically in order to transmit information. |
| Noise | Unwanted random disturbances superimposed on a signal which tend to obscure that signal. |
| Noise Floor | The level of noise intrinsic to a system that represents the minimum limit at which input signals can be observed; ultimately limited by thermal noise (kTB). |
| Noise Bandwidth (NBW) | The exact bandwidth of a flter that is used to calculate the absolute power of noise or noise-like signals in dBm/Hz. |
| Probability of Intercept | The certainty to which a signal can be detected within defned parameters. |
| Real-Time Bandwidth | The frequency span over which realtime seamless capture can be performed, which is a function of the digitizer and the IF bandwidth of a Real-Time Spectrum Analyzer. |
| Real-Time Seamless Capture | The ability to acquire and store an uninterrupted series of time domain samples that represent the behavior of an RF signal over a long period of time. |
| Real-Time Spectrum Analysis | A spectrum analysis technique based on Discrete Fourier Transforms (DFT) that is capable of continuously analyzing a bandwidth of interest without time gaps. Real-Time Spectrum Analysis provides 100% probability of display and trigger of transient signal fuctuations within the specifed span, resolution bandwidth and time parameters. |
| Real-Time Spectrum Analyzer | Instrument capable of measuring elusive RF events in RF signals, triggering on those events, seamlessly capturing them into memory, and analyzing them in the frequency, time, and modulation domains. |
| Reference Level | The signal level represented by the uppermost graticule line of the analyzer display. |
| Resolution Bandwidth (RBW) | The width of the narrowest measurable band of frequencies in a spectrum analyzer display. The RBW determines the analyzer’s ability to resolve closely spaced signal components. |
| Sensitivity | Measure of a spectrum analyzer’s ability to display minimum level signals, usually expressed as Displayed Average Noise Level (DANL). |
| Spectrogram | Frequency vs. Time vs. amplitude display where the frequency is represented on x-axis and time on the y-axis. The power is expressed by the color. |
| Spectrum | The frequency domain representation of a signal showing the power distribution of its spectral component versus frequency. |
| Spectrum Analysis | Measurement technique for determining the frequency content of an RF signal. |
| Vector Signal Analysis | Measurement technique for charactering the modulation of an RF signal. Vector analysis takes both magnitude and phase into account. |
Acronym Reference
| ACP | Adjacent Channel Power |
| ADC | Analog-to-Digital Converter |
| AM | Amplitude Modulation |
| BH4B | Blackman-Harris 4B Window |
| BW | Bandwidth |
| CCDF | Complementary Cumulative Distribution Function |
| CDMA | Code Division Multiple Access |
| CW | Continuous Wave |
| dB | Decibel |
| dBfs | dB Full Scale |
| DDC | Digital Downconverter |
| DFT | Discrete Fourier Transform |
| DPX | Digital Phosphor Display, Spectrum, etc. |
| DSP | Digital Signal Processing |
| EVM | Error Vector Magnitude |
| FFT | Fast Fourier Transform |
| FM | Frequency Modulation |
| FSK | Frequency Shift Keying |
| IF | Intermediate Frequency |
| IQ | In-Phase Quadrature |
| LO | Local Oscillator |
| NBW | Noise Bandwidth |
| OFDM | Orthogonal Frequency Division Multiplexing |
| PAR | Peak-Average Ratio |
| PM | Phase Modulation |
| POI | Probability of Intercept |
| PRBS | Pseudorandom Binary Sequence |
| PSK | Phase Shift Keying |
| QAM | Quadrature Amplitude Modulation |
| QPSK | Quadrature Phase Shift Keying |
| RBW | Resolution Bandwidth |
| RF | Radio Frequency |
| RMS | Root Mean Square |
| RTSA | Real-Time Spectrum Analyzer |
| SA | Spectrum Analyze |
| VSA | Vector Signal Analyzer |