Abbreviations
| ° | Convolution |
| * | Complex conjugation |
| ≈ | Is approximately equal to |
 |
Is defined as |
 |
Is much less than |
 |
Is much greater than |
| ∝ | Is proportional to |
| ϕ(f) | Phase of transfer function in radians, a function of frequency f; also called “phase response” |
| ϕ | Azimuth angle in spherical coordinates |
| σ | Standard deviation |
| θ | Polar angle in spherical coordinates |
| θ(t) | Signal phase in radians as a function of time t |
| 8PSK | 8-ary phase-shift-keying |
| 16QAM | 16-ary quadrature amplitude modulation |
| AC | Alternating current |
| ADC | Analog-to-digital converter |
| A/D | Analog-to-digital converter |
| A(f) | Signal-amplitude multiplication function of a filter as a function of frequency f; called for shorthand the “amplitude function” of the filter |
| AIAA | American Institute of Aeronautics and Astronautics, Inc. |
| ALC | Automatic level control |
| A-to-D | Analog-to-digital (converter) |
| AWGN | Additive white Gaussian noise |
| B | Bandwidth in Hz |
| BER | Bit error rate |
| BFN | Beam-forming network |
| BL | Loop bandwidth (one-sided baseband) of phase-locked loop |
| BOL | Beginning of life |
| BPF | Bandpass filter |
| BPSK | Binary phase-shift-keying |
| C | Carrier or signal power in a given bandwidth |
| CAMP | Channel amplifier ... |
