1978-05-17
1979-12-11
Cooper, William C.
H04Q 318
Patent
active
041784855
ABSTRACT:
A transformerless bidirectional amplifier useful in a balanced two wire to single wire line circuit, which blocks common mode signals and allows full control of signal levels, impedances, etc. A differential amplifier circuit is connected to the balanced wires, and has its output connected through a buffer amplifier to a single unbalanced wire. A second differential amplifier has its respective input terminals connected to the input and output of the buffer amplifier. The output of the second differential amplifier is connected to one of the balanced wires, and through a resistor to one of the inputs of the first differential amplifier which is connected to the other of the two balanced wires. The value of the latter resistor is such as to apply sufficient output signal from the second differential amplifier to the first differential amplifier so as to cancel a signal from the second differential amplifier which is applied to the first differential amplifier via the first wire of the balanced pair. The second differential amplifier exhibits different gains for the respective two signals applied to its individual inputs which are from the output of the first differential amplifier, whereby they are cancelled.
REFERENCES:
patent: 4007335 (1977-02-01), Hetherington et al.
patent: 4020294 (1977-04-01), Kitajewski et al.
Beirne Patrick R.
Cowpland Michael C. J.
Cooper William C.
Mitel Corporation of Kanata
LandOfFree
Transformerless telephone line circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Transformerless telephone line circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transformerless telephone line circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-311989