local oscillator
Noun: A local oscillator is an electronic oscillator within a receiver that generates a stable, continuous signal at a specific frequency. This generated signal is mixed with an incoming radio frequency signal to produce new signals at different frequencies (specifically the sum and difference), a process essential for converting and processing signals in many radio, television, and communication systems.
The local oscillator is a core component in superheterodyne receivers. * The receiver's local oscillator was tuned to 1,455 kHz to convert the desired 1,000 kHz station to the standard 455 kHz intermediate frequency. * A malfunctioning local oscillator can cause the radio to receive no stations or produce distorted sound. * Engineers adjusted the local oscillator frequency to minimize image interference.
- Local Oscillator (LO) Leakage: A phenomenon where the signal generated by the local oscillator unintentionally radiates from the receiver's antenna or circuitry, potentially causing interference with other nearby devices.
- Phase Noise: Refers to short-term, random fluctuations in the phase of the signal generated by a local oscillator, which can degrade the performance of communication systems, particularly in digital and high-frequency applications.
- In modern software-defined radios (SDRs), the function of the local oscillator is often performed digitally.
- LO: A common abbreviation for local oscillator.
- Variable-Frequency Oscillator (VFO): A type of oscillator whose frequency can be varied, often used as the local oscillator in tunable receivers.
- Synthesizer (Frequency Synthesizer): A circuit that generates a wide range of precise frequencies from a single stable reference (like a crystal oscillator), commonly used as the local oscillator in modern equipment.
- Heterodyne: (Verb) The process of combining two signals (like the incoming signal and the local oscillator signal) to produce new frequencies.
- Beat Frequency Oscillator (BFO): A specific type of local oscillator used in communications receivers to generate an audible tone from continuous-wave (CW) Morse code or single-sideband (SSB) signals. While a BFO is a type of LO, not all LOs are BFOs.
- Reference Oscillator: A very stable oscillator used as a frequency reference. A local oscillator may be derived from or synchronized to a reference oscillator, but they are not identical; the LO's specific function is for frequency conversion.
- Local Oscillator Frequency (LO Frequency): The specific frequency generated by the local oscillator.
- Mixing / Frequency Mixing: The process where the local oscillator signal and the incoming signal are combined in a mixer circuit.
- Intermediate Frequency (IF): The lower, fixed frequency signal produced as a result of mixing the incoming signal with the local oscillator signal. The IF is easier to filter and amplify.
- Image Frequency: An unwanted input frequency that, when mixed with the local oscillator frequency, also produces the intermediate frequency, leading to potential interference.
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an oscillator whose output heterodynes with the incoming radio signal to produce sum and difference tones
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