Distortion
Double Headset
Drain Wire
Dry Pair / Dry Line
DSP
Dual Listen
Dual Listen
Option
Duplex /
Simplex
Dynamic
Microphone
headphone volume to diminish by a preset amount whenever a talk key is activated. This can help to prevent occasional feedback between the speaker and microphone due to volume settings, microphone placement, etc. For setup and usage, search for “Speaker Dim” in the keypanel manual index.
Distortion is the effect when the output of an electronic device contains undesired signals that were not present at the input. This is assuming that the electronic device is supposed to be a linear device. The undesired signals have a frequency or frequencies that are related to the input signal. If the frequency(ies) is/are harmonically related to a single frequency input, then the undesired signal is ‘harmonic” distortion. If the signal is the sum or difference of two input frequencies, then the distortion is called “intermodulation” distortion. If the distortion is the result of a pulse or step input, and the frequency(ies) is/are related to sums and differences of the frequencies determined by the Fourier transform of the input pulse or step input, the distortion is called “transient intermodulation distortion”. Distortion can occur both in active devices (e.g. amplifiers) or passive devices (e.g. transformers). Harmonic Distortion is measured in percentages or decibels below the fundamental signal. For example: a distortion of 0.1 percent is “60 dB down”. Intermodulation Distortion requires two input signals (say 1000 and 400 hertz) to be inserted and the sum and difference to be measured.
Headset with intercom in one ear and program in the other.
Headset with two earphones plus a microphone. It can be connected monaurally (same information, both ears) or binaurally (separate feed each ear). In binaural operation, the feed can be intercom in one ear and program in the other, or intercom channel A in one ear and intercom channel B in the other ear. Channels A and B are either conference line channels or other intercom feeds. To get a binaural feed requires a binaural/stereo capable user station such as BP320, BP325, Model 802, Model MCE325, or any station so optioned.
An uninsulated wire in contact with a shield throughout its length, and used for connecting (“terminating”) the shield.
A dry pair or dry line is a communications line that has audio signals but no direct current (DC) voltage or current.
Digital Signal Processor. Usually a microprocessor with two memory addressing capability. One memory is the program memory which tells the microprocessor what to do, and the second memory contains: data to be processed, intermediate results, and final results. The advantage of a DSP is its speed. It is fast enough to process analog (or audio) signals in real time, and is often used in that application. Some applications are system to system interfaces (e.g. Telos “Link” for interfacing a standard telephone line to an RTS™ Systems TW Intercom line).
This is either an option or feature of intercom user stations. Dual listen permits an operator to listen to two channels at once. This may be a mix of two channels to one ear, or in a binaural or stereo user station, one channel can be assigned to one ear and the other channel to the other ear. Dual Listen could also be an intercom channel and a program audio source. The dual listen pots are functionally configured in one of three ways: 1. One pot controls the audio of the channel actively used, and the second pot controls the audio of a monitored channel. 2. One pot is always one channel and the other pot is always the other channel. 3. On three channel systems, operation is similar to 1. except if the active channel and the monitored channel coincide, the monitor feed is blanked out to prevent a 6 dB increase in volume and feedback.
An option for user stations that allows a monaural mix of two channels. Usually the station has two volume controls, sometimes two concentric volume controls.
See Full Duplex, Half Duplex, or Simplex.
Converts sound pressure waves to electrical signals by means of a coil attached to a diaphragm moving in a magnetic field.
E
EA symbol for voltage used in electronics, and engineering. Also used as the symbol for the electric field (volts per meter).
