# US 5,332,982 A · Ladder-type electric filter device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,332,982 A
- Document ID: US5332982A
- Status: Granted
- Kind: A
- Application number: 07/910,729
- Filed: 1992-07-08
- Granted: 1994-07-26
- Earliest claimed: 1991-07-10
- Assignees: Ngk Spark Plug Co., Ltd.
- Inventors: Kenji Kawakami
- Web page: https://patentgrep.com/patent/US5332982A

## CPC

- H03H 9/605: {consisting of a ladder configuration}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

A ladder-type electric filter comprising an input terminal, an output terminal, a plurality of series-resonators connected in series between said input terminal and said output terminal and a plurality of parallel-resonators each connected in parallel to the associated series-resonator, wherein each series-resonator has capacitance greater than that of the preceding series-resonator for improving a group delay time characteristic.

## Claims

### Claim 1

A ladder-type electric filter comprising an input terminal, an output terminal and a plurality of resonator units connected between said input terminal and said output terminal, each resonator unit including a series-resonator and a parallel-resonator which are L connected, the series-resonators of said resonator units connected in series between said input terminal and said output terminal having capacitance values which increase in magnitude from the series-resonator of one of said plurality of resonator units arranged closest to said input terminal to the series-resonator of further one of said plurality of resonator units arranged closest to said output terminal.

### Claim 2 (depends on 1)

A ladder-type electric filter as claimed in claim 1, wherein the parallel-resonator in each resonator unit has a capacitance larger than that of the associated series-resonator of the same resonator unit.

### Claim 3 (depends on 1)

A ladder-type electric filter as claimed in claim 1, wherein two series-resonators are connected in series between said input and output terminals and two parallel-resonators are connected in parallel between said input and output terminals, a first series-resonator of said two series-resonators being connected to said output terminal and a second series-resonator of said two series-resonators being connected to said input terminal and said first series-resonator having a capacitance larger than that of said second series-resonator.

### Claim 4

A ladder-type electric filter comprising an input terminal, an output terminal and at least two resonator units connected between the input terminal and the output terminal, each resonator unit comprising a series-resonator and a parallel-resonator which are L connected, the series-resonator of one of said resonator units arranged closest to the output terminal having a capacitance larger than that of the series-resonator of another one of said resonator units arranged closest to the input terminal.

### Claim 5 (depends on 4)

A ladder-type electric filter as claimed in claim 4, wherein the parallel-resonator in each of said resonator units has a capacitance larger than that of the associated series-resonator of the same resonator unit.