at which cutoff frequency fc the interconnect cable has
a -3 dB loss of treble (Treble frequencies are attenuated)?
Which length [ d ] a cable can have to reach this damping?
How are high frequencies damped by the length of the cable?
Cables are characterized by the capacity of the cable between the conductors, the
resistance, inductance of the cable along the conductor, and the current crowding,
which boost the resistance at high frequencies.
The most interlinks cable usually have a capacitance from wire to wire of about Cspec = 100 pF per meter.
The line resistance, and the inductance is usually negligible in practice. Each wire
has an unavoidable cable capacitance, that leads to the damping of high
frequencies (cable loss). Because the input resistance (load) is large against the
small source output impedance, the input impedance (load) can mostly be neglected.
Cable impedance is a cable characteristics which is only valid for high frequency signals.
Multimeters use DC current for resistance measurements, so you cannot
measure the cable impedance using your multimeter or other simple measurement equipments
Calculating the treble cutoff frequency of a cable
Zout = Output impedance of the source impedance ( Pre Amp )
Cspec = Specific capacitance of the cable in pF per m cable lenghth
d = Length of the cable in meters
C = Cspec x d
Formula for the cutoff frequency of the treble damping:
Another frequently asked question:
How long can the cable be, without having too much treble loss?
Calculation of the length of a cable at -3 dB treble attenuation
Formula for the length of the cable d and a given cutoff frequency fc:
fc = Cutoff frequency at -3 dB treble loss
Zout = Output impedance of the source impedance ( Pre Amp )
Cspec = Capacitance in pF per m cable lenghth C = Cspecx d
Calculate Cable Length & High Frequency Loss
