Publisher Summary The registration of acoustic emission (AE) in friction is characterized by the simultaneous occurrence of continuous and discrete AE, a broad dynamic range of variation of the signal amplitude, the effect of acoustic, electrical, and electromagnetic noise. The validity of conclusions on the condition of friction units based on AE measurement data depends on many factors including the reliable selecting of signal from unwanted noises accompanying the signal. Therefore, when developing the instrumentation and equipment for studies of AE in friction, it is necessary to take measures to dejam noises and ghost signals attending tribotests and to provide a high signal-to-noise merit. AE instrumentation, such as any electronic measuring instruments experiences the effect of external noise and intrinsic electrical noise resulting in masking and distortion of data being registered. Sources of intrinsic noise are fluctuation phenomena occurring in the instrumentation including thermal noise, fluctuations of the number of charge carriers in semiconductors, the instability of leakage currents etc. External noise is caused by the influence of electromagnetic fields on components of electronic devices and electromechanical sensing devices. Acoustic and mechanical effects on the object under study and AE gages also produce external noise.