Circuit for the parallel coupling of audio frequency central-control transmitting stations in a wave band filter construction

DETAILED DESCRIPTION When using an audio frequency generator of the electrodynamic rotary type or a static forcibly commutated inverter, the resonant circuits C.
sub.
s, L.
sub.
s and C.
sub.
1, L.
sub.
1, and C.
sub.
2, L.
sub.
2 of FIG.
1 are tuned to the audio frequency.
The current I.
sub.
1 generates the input open-circuit voltage U.
sub.
p at the capacitor C.
sub.
1 of the four-terminal network (see FIG.
2), while at the same time generating output open-circuit voltage U.
sub.
m at the mutual inductance M in the equivalent diagram of FIG.
2 when the audio generator is in operation and connected to the resonant circuits.
Because of the impedance situation as a consequence of parallel circuit C.
sub.
1, L.
sub.
1 this circuit carries an amount of current greater than I.
sub.
2, the current flowing in system impedance 2.
Thus, the output open-circuit voltage U.
sub.
m appearing across mutual inductance M is only slightly influences by system impedance 2.
Because of this relationship, the mutual inductance M can be kept significantly smaller than inductance L.
sub.
2 of the system-side series resonant circuit C.
sub.
2, L.
sub.
2.
Thus, the voltage U.
sub.
2 appearing at system impedance 2 is primarily determined by the voltage drop at leakage resistance R.
sub.
2 of this series resonant circuit.
By suitably selecting inductance L.
sub.
2 and its quality factor, the voltage drop at R.
sub.
2 can be kept at a minimum.
The total impedance X.
sub.
s of the audio generator-side series resonant circuit and the total impedance X.
sub.
p of the parallel resonant circuit, in the case of on-load inverters, must have a certain relationship to one another.
This relationship should be confined to the range X.
sub.
s = 0.
3 X.
sub.
p to 1.
0 X.
sub.
p.
Results of computations as well as of practical experiments have demonstrated that the impedances must be in the proper ratio, even in the series resonant circuit itself.
A lower limit for a faultless functioning of the on-load inverter has been found to be: X.
sub.
s : X.
sub.
L.
sub.
s : X.
sub.
C.
sub.
s = 1 : 2 : 3 An economical limit for optimal results has been determined to be: X