Electric tone generator

Electric tone generators have replaced tuning fork and pitch pipe in psychology experiments, but themselves are being supeceded by computer programs that generate sounds and auditory stimuli at appropriate frequencies and time intervals

Pitch generators and audio generators
A pitch generator is a type of signal generator optimized for use in audio and acoustics applications. Pitch generators typically include sine waves over the audio frequency range (20 Hz–20 kHz). Sophisticated pitch generators will also include sweep generators (a function which varies the output frequency over a range, in order to make frequency-domain measurements), multipitch generators (which output several pitches simultaneously, and are used to check for intermodulation distortion and other non-linear effects), and tone bursts (used to measure response to transients). Pitch generators are typically used in conjunction with sound level meters, when measuring the acoustics of a room or a sound reproduction system, and/or with oscilloscopes or specialized audio analyzers.

Many pitch generators operate in the digital domain, producing output in various digital audio formats such as AES3, or SPDIF. Such generators may include special signals to stimulate various digital effects and problems, such as clipping, jitter, bit errors; they also often provide ways to manipulate the metadata associated with digital audio formats.

The term synthesizer is used for a device that generates audio signals for music, or that uses slightly more intricate methods.

Computer programs
Computer programs can be used to generate arbitrary waveforms on a general-purpose computer and output the waveform via an output interface. Such programs may be provided commercially or be freeware. Simple systems use a standard computer sound card as output device, limiting the accuracy of the output waveform and limiting frequency to lie within the audio-frequency band.