【発明の名称】集積化電気フイルタ - FUIRITSUPUSU FURUUIRANPENFUABURIKEN NV

Title:

【発明の名称】集積化電気フイルタ

Document Type and Number:

Japanese Patent JPH0683015

Kind Code:

B2

Abstract:

A continuous time electrical filter fabricated as an integrated circuit includes capacitors (CO,CN) and resistors (R₁,R2). Since capacitors and resistors are difficult to integrate with accurately defined values a trimming circuit is provided which operates switches (S1-SN) to select appropriate ones of the capacitors (CN) to accurately define the cut-off frequency of the filter.The trimming circuit comprises a capacitor (TC2) which is charged through a resistor TR1 during a first period and which is discharged in incremental steps by capacitor (TC1). The number of incremental steps is counted by a counter (11) and transferred to a register (13). The outputs (S1-SN) of the register (13) control the switches (S1-SN). Instead of adjusting the value of the capacitors in the filter the values of the resistors may be adjusted. If this is done a convenient procedure is to short out selected portions of the resistors. More than one capacitor or resistor may be adjusted using a single counter and register.

Inventors:

JON BARII HYUUZU

Application Number:

JP2805486A

Publication Date:

October 19, 1994

Filing Date:

February 13, 1986

Export Citation:

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Assignee:

FUIRITSUPUSU FURUUIRANPENFUABURIKEN NV

International Classes:

H03H11/12; H03H1/02; H03H11/00; H03H11/04; H03H19/00; (IPC1-7): H03H11/12; H03H11/04

Domestic Patent References:

JP59107622A

Attorney, Agent or Firm:

Akihide Sugimura (1 outside)

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