# MiscEl: Cable calculations

 Back to MiscEl main page Write a message to author Calculations on a cable, one or two wires with otional shield.
The cable is simulated with a number of seperate RLC sections

### Analyze input fields

 C Capacity between wires for one meter cable Cshield Capacity between one wire and shield L Inductance for one meter cable Rcable DC resistance for one meter of wire Rshield DC resistance for one meter of shield Length Total length of cable Rs Source impedance Rl Load impedance Curve plot Show a curveplot of frequence responce Waveforms Try cable with different waveforms Input/output Use a complex source/load network

### Analyze output fields

 -3 dB Freq This is calculated form RCL and ignoring any transmission line effects Cable Zo Impedance of cable at specified frequence Signal velocity Speed of signal at specified frequence, shown in absolute speed and percent of c Gain Gain of cable (Will be below 1) Phase Phase of output signal Signal in B Crosstalk to B wire Phase of B Phase of signal in B wire Signal in gnd Signal in gnd connection

### Signal input fields

This tab will do a more detailed analysis with a specific signal.
 Freq Calculate cable parameters and transmission fr this frequence Volt (RMS) Analyze with this voltage dBm Specify signal as dB with reference at 1mW over 600 ohm

### Signal output fields

 RMS voltage RMS voltage and dB level (Ref: 1mW over 600 ohm) Peak-peak voltage Above value multiplied by sqrt(8) Slew rate The maximum slew rate of the voltage Source cable i/Source cable current Maximum current going into the cable to charge/discharge the cable capacity Source load current Maximum current used to supply the load Noise floor Comparing the signal to "Johnson" noise

### Config

 Limit Used when calculating cutoff frequence, usual 3 dB Freq n Analyze at these frequences, write DC to do a DC analyse Sections How many section to do the calculations on, more sections give better result but are slower

### Zo to L

Convert a Zo specification to inductance
 Zo Impedance of cable C Capacitance of cable R DC resistance of cable Copy to analyze Copy entered and calculated parameters to analyze page