A device that alters the frequency composition of a signal is called?

The correct term for a device that alters the frequency composition of a signal is a filter. Filters are essential components in signal processing that allow certain frequency components to pass through while attenuating others. This selectivity is crucial in various applications such as audio processing, telecommunications, and biomedical instrumentation, where specific frequency ranges may need to be enhanced or suppressed to improve signal quality or isolate desired information.

Filters can be categorized into various types, including low-pass, high-pass, band-pass, and band-stop filters, based on their function in the frequency spectrum. By manipulating the frequency content of the signal, filters can effectively enhance the clarity of the desired signal and reduce background noise or unwanted frequencies.

The other options presented do not perform the same function. Conductors are materials that allow the flow of electric current but do not modify frequency content. Transducers convert energy from one form to another, such as from sound to electrical signals or vice versa, but they also do not specifically focus on altering frequency compositions. Capacitors are components that store and release electrical energy in a circuit; while they can influence how signals behave at different frequencies (especially in filter circuits), they do not independently filter or modify the frequency composition of a signal in the way that filters do.