Title: Electronic speech circuit for a central battery telephone set

Abstract: An electronic speech circuit for a central battery telephone set in the form of a Wheatstone bridge has for one arm of the bridge the impedance of the incoming line to the set and for another arm an impedance mainly equal to the line impedance. The remaining arms consist of resistance impedances, preferably resistors. The DC-terminals of the transmitter amplifier are connected in the bridge diagonal which is connected between the two resistors, and the other bridge diagonal is formed by the signal path of the receiver amplifier, the DC-terminals of which are connected to one of the resistors and to the line simulating impedance.

Do you think this is a good invention? Vote now:

Votes so far: For:(0) Against:(0)
Other info:

Inventors: Mersich, Laszlo (Tyreso, SW)

Application Number: 549664
Filing Date: 1975-02-13
Publication_date: 1976-08-10
Assignee: Telefonaktiebolaget L M Ericsson (Stockholm, SW)
Primary Class(es): 379/395 379/392
Other Classes:
US Patent Ref:

3462560	Aug, 1969	Holzman	179/81.
3742153	Jun, 1973	Matsuda	179/81.
3748400	Jul, 1973	Ritz	179/81.

Other Refs:
Primary Examiner: Claffy, Kathleen H.
Assistant Examiner: Popek, Joseph A.
Attorney: Hane, Baxley & Spiecens