Apparatus for generating ungrounded voltages
AssigneeSiemens Aktiengesellschaft
InventorAdolf Haass
Life of this patent
Estimating the term…
Abstract
A circuit arrangement for facilitating the determination of a wire break in a line interconnecting a plurality of subscriber stations in a direct current, keyed data transmission system. Each subscriber station is equipped with a bridge circuit containing a balancing resistance, bridge resistances and a fourth arm formed by the transmission line. A transmitter is connected in one diagonal of the bridge, and the receiver in another. An operational amplifier forms a first voltage source connected in the line circuit and a second voltage source connected in the balancing arm generates a monitoring current flow. The two operational amplifiers forming these voltage sources function as differential amplifiers, and the voltages are adjusted to the same value by a single balancing operation.
Claims1
Apparatus for determining the existence of a wire break in a transmission line connecting subscriber stations in a direct current, keyed data transmission system comprising:
- bridge circuit means in each said subscriber station, said bridge circuit comprising four arms constituted by said transmission line, balancing resistance means and first and second bridge resistances,
- transmitter means connected into one diagonal of said bridge circuit means, said transmitter means having at least first and second terminals,
- receiver means connected into another diagonal of said bridge circuit,
- first and second operational amplifier means, each having an inverting input and a non-inverting input and an output,
- a first terminal of said transmitter means being connected to said noninverting input of said first operataonal amplifier means,
- said output of said first operational amplifier means being connected to said transmission line and to said non-inverting input of said second operational amplifier means,
- a constant current source,
- first and second resistances,
- said output of said second operational amplifier means being connected to an end of said balancing resistance means, said end being connected to said output terminal of said second operational amplifier means and then to said transmission line, said output of said operational amplifier means being further connected to a series connection of said first resistance, a first junction point, said second resistance, a second junction point and said constant current source, said series combination being series connected to said second terminal of said transmitter means,
- said first junction point being connected to said inverting input of said second operational amplifier means and said second junction point being connected to said inverting input of said first operational amplifier means,
- said first bridge resistance being connected to said second terminal of said transmitter means and to said transmission line, and
- monitoring means connected across said first bridge resistance and for emitting a signal when there is no voltage drop thereacross,
- said second terminal of said transmitting means being further connected to the connecting point between said first and second bridge resistances.
Dependencies are inferred from the claim text.