No, it is not.
discrete
The two main kinds are discrete and continuous.
discrete because the signal of an alarm is periodic.
The analog signal is converted to discrete signal. Even after the conversion, the frequency of the actual signal still remains the same. If the frequency of the discrete signal is different from the analog signal, the reconstructed signal would be different again. This is not what we expect. So base spectrum for similar signals have same frequencies, whether they are discrete or analog. Why do the repetitions occur? The original analog signal is multiplied with a dirac pattern. The base frequency is then shifted to the places, where diracs are available. So long the diracs keep repeating, the base frequency do repeats. Hope you are convinced with my answer
Species
To answer this properly more context is needed but frequency is in most contexts continuous.
The frequency domain of a voice signal is normally continuous because voice is a nonperiodic signal.
FDM stnds for frequency division multiplexing and it is used only in case of analog signals because analog signals are continuous in nature and the signal have frequency. TDM-stands for time division multiplexing and it is used only in case of digital signals because digital signals are discrete in nature and are in the form of 0 and 1s. and are time dependent.
A photon is a small discrete unit of energy that is associated with light. It behaves both like a particle and a wave, carrying a specific amount of energy depending on its frequency.
In signal processing, sampling is the reduction of a continuous signal to a discrete signal. A common example is the conversion of a sound wave (a continuous signal) to a sequence of samples (a discrete-time signal).
The frequency of a guitar note can be determined by measuring the number of vibrations per second. This frequency is represented as a continuous value because it can vary smoothly across a range of pitches.
A Z-transform is a mathematical transform which converts a discrete time-domain signal into a complex frequency-domain representation.