Plug-in adjustable attenuator construction

Claim 2

An adustable attenuator for a balanced, two conductor, low frequency telecommunication line, comprising a fixed pad component having input and output means for connecting the component in series with such a line, circuit means in said fixed pad component comprising plural, series-connected attenuation network portions interconnecting said input and output means, each of said portions including a different set of selected impedance elements, and plural pad adjusting components removably connected to said fixed pad component, each of said pad adjusting components including impedance means combining with a different one of said network portions to provide a plurality of balanced attenuation networks connected in series between said input and output means, which networks cooperate to provide substantially equal attenuator input and output impedances.

Claim 3

The attenuator of claim 1, wherein said input and output means comprises a pair of input terminals and a pair of output terminals, and said circuit means comprises a series-connected pair of network portions interconnecting said pairs of terminals, said set of selected impedance elements in one of said network portions including first and second resistance elements, said set of selected impedance elements in the other of said network portions including first and second series-connected pairs of resistance elements, said first element and said first pair being connected in series between one of said input terminals and one of said output terminals, and second element and second pair being connected in series between the other of said input terminals and the other of said output terminals.

Claim 4

The attenuator of claim 2, comprising a pair of pad adjusting components connected to said fixed pad component, one of said pair comprising first resistance means (52a) combining with said first (72) and second (78) resistance elements to provide a bridged, balanced-square resistance network (52), and the other of said pair comprising second resistance means (50a) combining with said first (68, 70) and second (74, 76) series-connected pairs of resistance elements to provide a bridged, balanced-H resistance network (50).

Claim 5

The attenuator of claim 3, wherein said first and second resistance elements (72 and 78) have the same resistance value, and each resistance element in said first and second pair (68, 70 and 74, 76) has the same resistance value, said first resistance means (52a) includes third (62) and fourth (66) resistance elements having the same resistance value and combining with said first and second elements to form with them a series-connected closed loop, and fifth (60) and sixth (64) resistance elements having the same resistance value and respectively combining in shunt relation with said first and second resistance elements to thereby bridge said elements, and said second resistance means (50a) includes a seventh (56) resistance element combining with said first and second series-connected pairs to interconnect the junction between the elements of said first series-connected pair (68, 70) and the junction between the elements of said second series-connected pair (74, 76), and eighth (58) and ninth (54) resistance elements having the same resistance value and respectively combining in shunt relation with said first and second series-connected pairs of elements to bridge said pairs.

Claim 6

The attenuator of claim 4, wherein said attentuator is for a line having a nominal 600 ohm impedance, and, accordingly, said first and second resistance elements (72, 78) have a value of about 31.14 ohms, each resistance element in said first and second series-connected pairs (68, 70, 74, 76) has a value of about 300 ohms, and said third and fourth (62, 66), fifth and sixth (60, 64), seventh (56), and eighth and ninth (58, 54) resistance elements have the following values for different attenuations in said networks (52, 50) as follows:

Claim 7

An incrementally adjustable attenuator for a balanced, two conductor, low frequency telecommunication line, comprising a first pad component comprising a receptacle base having a pair of sockets therein, and additionally having input and output terminals for connecting said component in series with such a line, circuit means in said first pad component comprising a pair of attenuation network portions interconnecting said input and output terminals, each of said pair including a set of selected impedance elements, a second pad component comprising a first plug removably received in one of said sockets, and impedance means in said plug for combining with the impedance elements in one of said pair of network portions to provide a first attenuation network, and a third pad component comprising a second plug removably received in the other of said sockets, and impedance means in said second plug for combining with the impedance elements in the other of said pair of network portions to provide a second attenuation network.

Claim 8

An incrementally adjustable attenuator for a balanced, two conductor, low frequency telecommunication line, comprising a first pad component comprising a receptacle base having a pair of sockets therein, and additionally having input and output terminals for connecting said component in series with such a line, circuit means in said first pad component comprising a pair of attenuation network portions interconnecting said input and output terminals, each of said pair including a set of selected impedance elements, a second pad component comprising a first plug removably received in one of said sockets, and impedance means in said plug for combining with the impedance elements in one of said pair of network portions to provide a first attenuation network, and a third pad component comprising a second plug removably received in the other of said sockets, and impedance means in said second plug for combining with the impedance elements in the other of said pair of network portions to provide a second attenuation network.

Claim 9

The attenuator of claim 6, wherein said first and second plugs each include a projecting tongue configured for removable insertion in the appropriate one of said one and other sockets, the tongues of said plugs having conductive expanses thereon connected to impedance elements in said plugs, which elements comprise said impedance means, and said base includes electrical contact means in said sockets connected to said selected impedance elements in the base for contacting said conductive expanses and establishing electrical connections between certain ones of said selected impedance elements and certain ones of said impedance elements in the plugs to provide said attenuation networks.

Claim 10

The attenuator of claim 7, wherein said one and other sockets are sized differently, one from the other, and the tongues of the plugs received in said sockets have sizes corresponding to the sizes of the respective sockets.

Claim 11

The attenuator of claim 7, wherein said receptacle base further includes circuit board means bearing said selected impedance elements, and means establishing electrical connections between the impedance elements on the said board means and said contact means and input and output terminals.

Claim 12

The attenuator of claim 7, wherein said selected impedance elements in said base and said impedance elements in said plugs comprise electrical resistance elements, and said first and second attenuation networks are bridged, balanced-H and bridged, balanced-square resistance networks, respectively.

Claim 13

The attenuator of claim 10, wherein said first and second networks are connected in series between said input and output terminals, and the impedance elements providing said first and second networks are of suitable impedance values for producing an integral value and a proper fractional value, respectively, of attenuation in a line connected to said input and output terminals.

Claim 14

An incrementally adjustable attenuation system for use in combination with a balanced, two conductor, low frequency telecommunication line, comprising a receptacle base having a pair of sockets therein, a pair of input terminals, a pair of output terminals, and electrical circuit means comprising a series-connected pair of attenuation network protions interconnecting said input and output terminals, each of said portions being associated with a different one of said sockets, a first plug-in part configured for removable insertion in one of said pair of sockets, and including circuit means for combining with the network portion associated with said one socket when inserted to provide a first attenuation network, and a second plug-in part configured for removable insertion in the other of said pair of sockets, and including circuit means for combining with the network portion associated with said other socket when inserted to pRovide a second attenuation network.

Claim 15

An incrementally adjustable attenuation system for use in combination with a balanced, two conductor, low frequency telecommunication line, comprising a receptacle base having a pair of sockets therein, a pair of input terminals, a pair of output terminals, and electrical circuit means comprising a series-connected pair of attenuation network protions interconnecting said input and output terminals, each of said portions being associated with a different one of said sockets, a first plug-in part configured for removable insertion in one of said pair of sockets, and including circuit means for combining with the network portion associated with said one socket when inserted to provide a first attenuation network, and a second plug-in part configured for removable insertion in the other of said pair of sockets, and including circuit means for combining with the network portion associated with said other socket when inserted to pRovide a second attenuation network.

Claim 16

The system of claim 12, wherein said first and second plug-in parts each include a body portion, and means defining a tongue projecting from said portion for insertion in the appropriate one of said one and other sockets, each of said tongues having conductive expanses thereon connected to resistance elements in the body portions of their respective plug-in parts, which elements comprise said circuit means in said parts, and said base includes electrical contact means in each of said pair of sockets connected to resistance elements comprising each socket''s associated network portion for contacting the conductive expanses on a plug-in part''s tongue upon its insertion into the appropriate socket and establishing electrical connections between the resistance elements in the part''s body portion and the resistance elements in the socket''s associated network portion.

Claim 17

The system of claim 13, wherein said receptacle base further includes circuit board means bearing said resistance elements comprising said network portions, and means establishing electrical connections between said resistance elements and said contact means and input and output terminals.

Claim 18

In a balanced, two conductor, low frequency telecommunication line, an incrementally adjustable attenuator comprising, a fixed pad element in series with said line, said element including a receptacle base having a pair of sockets therein, input and output terminal means connecting the element in series with said line, and a series-connected pair of circuit portions interconnecting said input and output terminal means, each of said portions being associated with a different one of said sockets and each including selected resistances in series with the conductors of said lines, a first attenuation modifier element comprising a plug-in part removably received in one of said sockets, and including first resistance means combining with the selected resistances in the circuit portion associated with said one socket to produce one value of attenuation in said line, and a second attenuation modifier element comprising another plug-in part removably received in the other of said sockets and including second resistance means combining with the selected resistances in the circuit portion associated with said other socket to produce another value of attenuation in said line, said one and other values adding to produce a predetermined, desired attenuation in the line.

Claim 19

In a balanced, two conductor, low frequency telecommunication line, an incrementally adjustable attenuator comprising, a fixed pad element in series with said line, said element including a receptacle base having a pair of sockets therein, input and output terminal means connecting the element in series with said line, and a series-connected pair of circuit portions interconnecting said input and output terminal means, each of said portions being associated with a different one of said sockets and each including selected resistances in series with the conductors of said lines, a first attenuation modifier element comprising a plug-in part removably received in one of said sockets, and including first resistance means combining with the selected resistances in the circuit portion associated with said one socket to produce one value of attenuation in said line, and a second attenuation modifier element comprising another plug-in part removably received in the other of said sockets and including second resistance means combining with the selected resistances in the circuit portion associated with said other socket to produce another value of attenuation in said line, said one and other values adding to produce a predetermined, desired attenuation in the line.

Claim 20

The attenuator of claim 15, wherein said first resistance means combines with the selected resistances in the circuit portion associated with said other socket to produce an integral value of attenuation in said line, and said second resistance means combines with the selected resistances in the circuit portion associated with said other socket to produce a proper fractional value of attenuation in said line.

Claim 21

The attenuator of claim 15, wherein said input and output terminal means includes a pair of input terminals and a pair of output terminals, one of said circuit portions comprises a first resistance in series with said one conductor and a second resistance in series with said other conductor of the line, and the other of said circuit portions comprises a first series-connected pair of resistances in series with one conductor and a second series-connected pair of resistances in series with the other conductor of said line, said first resistance and said first pair being connected in series between one of said input terminals and one of said output terminals, and said second resistance and said second pair being connected in series between the other of said input terminals and the other of said output terminals.

Claim 22

The attenuator of claim 17, wherein said first and second resistances have the same resistance value and each resistance in said first and second pairs has the same resistance value.