P5056

ETALDOC 776/5

Page 3 of 5

June 2005

MATCHING RECOMMENDATIONS

The following recommendations start with the simplest implementations and progress to enhanced

performance utilizing an additional component.

Good performance is achieved even with the simplest

configurations.

The implementations assume a low impedance balanced TX drive and a relatively high

impedance RX input, as is commonly available, though use with other TX/RX arrangements is

straightforward.

Note that there are no changes to components on the line side, or in the hybrid, whether

600

Ω or complex reference impedance selected, thus assisting country configuration. For complex

impedance, the matching circuits derived are suitable for reference impedances of the type 270 + 750//150nF

e.g. European CTR21 and 220 + 820//120nF (or 115nF) e.g. Australia, South Africa, etc., and yield similar

performance characteristics. For other impedances, please contact Profec Technologies.

Minimum Cost Implementations

Improved matching

Patented

LINE

270

(220)

750

(820)

150nF

(120nF)

910

100nF*

* Note: 100nF c a pac itor should have a tempera ture stable dielec tric

82

European CTR21/(Australia, etc.)

Fig. 3

RXA

TXA2

TXA1

μ

22 F

600Ω

Fig . 4

LINE

600

10nF

510

RXA

TXA2

TXA1

μ

22 F

10nF

LINE

270

(220)

750

(820)

μ

22 F

150nF

(120nF)

820

100nF*

* Note: 100nF c a pac itor should have a tempera ture stable dielec tric

82

European CTR21/(Australia, etc.)

Fig. 5

RXA

TXA2

TXA1

600Ω

Fig . 2

LINE

600

510

RXA

TXA2

TXA1

μ

22 F