8 . 0 | G l o s s a r y |
In this section many of the terms used throughout this manual are explained in more detail.
Active
Active electronic circuits are those which are capable of voltage and power gain by using transistors and integrated circuits.
Amplitude
Refers to the voltage level or intensity of a signal, and is usually measured in volts or decibels.
Balanced
A three wire connection in which two of the wires carry the signal information, the third acts as a shield tied to chassis ground. The two signal lines are of opposite polarity (out of phase by 180 degrees) at any given moment in time, and are of equal potential with respect to ground. Balanced connections are used to help reject induced hum and noise in system interconnections.
Binding Post
A type of connector that maybe used for either a bare wire or a wire terminated in a 4mm plug.
Bridge Mode
This applies to a method of combining two power amplifier channels to make one channel capable of providing approximately twice the power into a single load. This load must be connected across the two positive channel outputs.
Clip or Clipping
The term used to describe an overdrive condition in a piece of equipment. A clipped signal is distorted and will sound harsh. Applying a heavily clipped signal to a loudspeaker, whilst not unduly affecting the amplifier, may cause speaker damage.
dB
A unit for expressing the ratio between two signal levels for comparison purposes. On its own it has no absolute level meaning. Rather, it is a logarithmic ratio used to express the differences between two amounts or levels. Positive numbers indicate an increase, and negative ones a decrease.
Some useful ratios are:
+3dB = Double Power
+6dB = x 2 Voltage or x 4 Power +10dB = x 3 Voltage or x 10 Power +20dB = x 10 Voltage or x 100 Power
dBm
The addition of ‘m’ after dB indicates an absolute scaling for the dB ratio. Instead of a ratio, the dB becomes a measure of voltage. 0dBm = a power level of 1 milliwatt into a load of 600 ohms. It is also loosely used to describe signal voltage in 600 ohm circuits.
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