Insertion loss equalization device

Claim 2

A loss equalizer device for equalizing the loss of a conventional filter over a given passband and comprising: crystal plate means; first and second pairs of electrodes coated on said crystal plate with each pair of electrodes comprising a coated area on substantially coinciding opposite sides of said crystal plate; a pair of input terminals connected to said first pair of electrodes; a misterminated impedance means having an impedance different from the midband impedance of said device connected to said second pair of electrodes to provide greater loss at the center of said passband than at points within said passband and near the shoulders thereof; and means for cascading said loss equalizer with said conventional filter.

Claim 3

A loss equalizer device in accordance with claim 1 in which said means for cascading said loss equalizer with said conventional filter comprises: T network means comprising first, second, and third resistive means forming the left half of the crossbar of the T network, the right half of the crossbar of the T network, and the leg of the T network, respectively; said first and third resistive means comprising said misterminated impedance means and being connected across said second pair of electrodes; and said second and third resistive means comprising the coupling impedance to said conventional filter.

Claim 4

A loss equalizer device in accordance with claim 1 in which: said pairs of electrodes are positioned a given distance apart and form a pair of resonators coupled together through that portion of the crystal plate lying therebetween; said given distance being sufficient to substantially isolate each resonator one from the other with respect to electrical coupling but sufficiently close to permit mechanical coupling between said resonators.

Claim 5

A loss equalizer device in accordance with claim 3 in which said means for cascading said loss equalizer with said conventional filter comprises: T network means comprising first, second, and third resistive means forming the left half of the crossbar of the T network, the right half of the crossbar of the T network, and the leg of the T network, respectively; said first and third resistive means comprising said misterminated impedance means and being connected across said second pair of electrodes; and said second and third resistive means comprising the coupling impedance to said conventional filter.

Claim 6

In combination with a crystal filter having a pair of input terminals and a passband with rounded corners and a terminating impedance Z1, a loss equalizer device comprising: crystal plate means; at least two pairs of electrodes on said crystal plate with the two electrodes of each pair being positioned coincidentally on opposite sides of said crystal plate; a paIr of terminals connected to a first pair of said two pairs of electrodes; and two port terminating impedance means having the first port connected to said crystal filter and presenting an impedance substantially equal to 21 thereto, and the second port connected to the second pair of electrodes of said loss equalizer device and presenting an impedance Z2 thereto, which impedance Z2 constitutes a mismatch with said loss equalizer device to provide a greater loss at the center of said passband than at points within said passband but near the shoulders thereof.

Claim 7

In combination with a crystal filter having a pair of input terminals and a passband with rounded corners and a terminating impedance Z1, a loss equalizer device comprising: crystal plate means; at least two pairs of electrodes on said crystal plate with the two electrodes of each pair being positioned coincidentally on opposite sides of said crystal plate; a paIr of terminals connected to a first pair of said two pairs of electrodes; and two port terminating impedance means having the first port connected to said crystal filter and presenting an impedance substantially equal to 21 thereto, and the second port connected to the second pair of electrodes of said loss equalizer device and presenting an impedance Z2 thereto, which impedance Z2 constitutes a mismatch with said loss equalizer device to provide a greater loss at the center of said passband than at points within said passband but near the shoulders thereof.

Claim 8

The combination in accordance with claim 5 in which: said two port terminating impedance means comprises first, second, and third resistive means forming the left half of the crossbar, the right half of the crossbar, and the leg of a T network pad, respectively; said second pair of electrodes of said loss equalizer device being connected across first and third resistive means; and said input terminals of said crystal filter being connected across said second and third resistive means.

Claim 9

The combination in accordance with claim 5 in which: said pairs of electrodes are positioned a given distance apart and form a pair of resonators coupled together through that portion of the crystal plate lying therebetween; said given distance being sufficient to substantially isolate each resonator one from the other with respect to electrical coupling but sufficiently close to permit mechanical coupling between said resonators.

Claim 10

The combination in accordance with claim 7 in which: said two port terminating impedance means comprises first, second, and third resistive means forming the left half of the crossbar, the right half of the crossbar, and the leg of a T network pad, respectively; said second pair of electrodes of said loss equalizer device being connected across said first and third resistive means; and said input terminals of said crystal filter being connected across said second and third resistive means.

Claim 11

In a system utilizing conventional filter means having input and output means and a given frequency passband, a loss equalizer device for equalizing the loss of said conventional filter over said given passband and comprising: crystal plate means; first and second pairs of electrodes coated on said crystal plate with each pair of electrodes comprising a coated area on substantially coinciding opposite sides of said crystal plate; a pair of input terminals connected to said first pair of electrodes; a misterminated impedance means having an impedance different from the midband impedance of said device connected to said second pair of electrodes to provide greater loss at the center of said passband than at points within said passband and near the shoulders thereof; and means for cascading said loss equalizer device with said conventional filter means and comprising two port impedance means constructed to present first and second impedances Z1 and Zto its first and second ports, respectively; said first port being connected to the output means of said conventional filter means; and said second port being connected to the input terminals of said loss equalizer device and comprising said misterminated impedance for said loss equalizer device.

Claim 12

In a system utilizing conventional filter means having input and output means and a given frequency passband, a loss equalizer device for equalizing the loss of said conventional filter over said given passband and comprising: crystal plate means; first and second pairs of electrodes coated on said crystal plate with each pair of electrodes comprising a coated area on substantially coinciding opposite sides of said crystal plate; a pair of input terminals connected to said first pair of electrodes; a misterminated impedance means having an impedance different from the midband impedance of said device connected to said second pair of electrodes to provide greater loss at the center of said passband than at points within said passband and near the shoulders thereof; and means for cascading said loss equalizer device with said conventional filter means and comprising two port impedance means constructed to present first and second impedances Z1 and Zto its first and second ports, respectively; said first port being connected to the output means of said conventional filter means; and said second port being connected to the input terminals of said loss equalizer device and comprising said misterminated impedance for said loss equalizer device.