The cutoff frequency is defined as the signal frequency at which the filter output is 3 dB below the input. Logarithmic - A mathematical term for the ratio of values expressed by the base 10 or e. If the base is 10, the logarithm is called common. If the base is e, the logarithm is called natural. Noise - Usually an undesired electronic signal that has no relationship to the desired signal in a system.
Noise is usually the result of unavoidable random electron motion in electronic devices.
Noise may be simulated mathematically by a random number generation process. Parallel Port - A port on the PC that handles a data stream in a parallel mode. That is, the data is sent out or received an 8 bit byte at a time on 8 lines or connector pins. Other lines or pins are used for handshaking or data transfer control. The standard IBM-PC parallel port interface is termed a Centronics port, based on the original use of the port as a printer interface.