A synthesizer which has the ability to record and digitize short lengths (samples) of arbitrary sounds, and uses these as its waveform source (as opposed to using oscillators or other waveform-generating circults). A sampler has the ability to pitch-shift a recorded sound to correspond to the key played on the keyboard, allowing non-musical sounds such as spoken words, automobile engines, pots and pans, etc., to be played.(The first sample ever recorded on the first sampler was a barking dog.)
The first samplers had little capability beyond simply recording and playing back sounds. However, modern samplers are usually equipped with most of the same sound-shaping components as other synthesizers -- VCFs, VCAs, and so on. Further, an essential component to modern sampling technique is the ability to loop part or all of a sample, in order to create an indefinitely sustainable tone, or a repeating phrase. Advanced samplers can play loops forwards and backwards, use different parts of the sample for attack, sustain, or release loops, or apply different processing to different parts of the loops. Other advanced capabilities include the ability to cut, paste, and merge blocks of samples; apply time, frequency, and formant shifting to samples, and draw or edit waveforms graphically.
Since the 1980s, samplers have been using pulse-code modulation (PCM) for digital sampling. The first PCM digital sampler was Toshiba's LMD-649, created in 1981 by engineer Kenji Murata for Japanese electronic music band Yellow Magic Orchestra, who used it for extensive sampling and looping in their 1981 album Technodelic. The LMD-649 played and recorded PCM samples at 12-bit audio depth and 50 kHz sampling rate, stored in 128 KB of dynamic RAM. The LMD-649 was also used by other Japanese synthpop artists in the early 1980s, including Chiemi Manabe and Logic System.