초록 ▼

A circuit is proposed for adjusting the loss provided to loops in digital loop carrier transmission systems. A constant current is supplied to the loop and the resulting voltage is measured to determine the resistance of the loop. This value is fed to a microprocessor with a look-up table which cont

A circuit is proposed for adjusting the loss provided to loops in digital loop carrier transmission systems. A constant current is supplied to the loop and the resulting voltage is measured to determine the resistance of the loop. This value is fed to a microprocessor with a look-up table which controls a programmable analog/digital converter. The loss at the output of the converter is a stepwise function based on the resistance of the customer loop.

대표청구항 ▼

A circuit for automatic adjustment of signal loss in loops of a digital loop transmission system comprising: means for providing a constant current to the loops; means for detecting a resulting dc voltage on the loops comprising a comparator with one input coupled to a capacitor and another input co

A circuit for automatic adjustment of signal loss in loops of a digital loop transmission system comprising: means for providing a constant current to the loops; means for detecting a resulting dc voltage on the loops comprising a comparator with one input coupled to a capacitor and another input coupled to the means for providing a constant current; a microprocessor coupled to said detecting means, said microprocessor including a look-up table for determining an amount of loss to be applied to the loops as a function of a resistance of the loops and said microprocessor being adapted to charge the capacitor; and a programmable analog/digital converter having an input coupled to a microprocessor look-up table output and an output providing an analog signal to the loops, the analog signal being adjusted in accordance with the microprocessor output.