Title:
【発明の名称】モノリシックHBT式能動同調可能帯域フィルタ
Document Type and Number:
Japanese Patent JP3002641
Kind Code:
B2
Abstract:
An active tuneable band-pass filter is provided which has a negative resistance circuit for generating a tuneable amount of negative resistance for a passive band-pass filter structure so as to compensate for resistive losses. The negative resistance circuit has a bipolar transistor with a base connected in shunt to the passive filter structure and a collector connected to a shunt inductive element. A negative resistance is generated at the base of the transistor and is applied to the passive filter structure. A coarse Q-factor tuning circuit is coupled to the emitter of the transistor for providing a coarse amount of tuning of the negative resistance. Also connected to the emitter terminal, is a fine tuning circuit for providing fine tuning of the negative resistance. The fine tuning may be achieved manually or automatically with a control circuit. The coarse and fine tuning capability provides a tuneable negative resistance which eliminates oscillations and compensates for resistive loss variations to realize improved q-factor.
Inventors:
Kevin W. Kobayashi
Application Number:
JP8130296A
Publication Date:
January 24, 2000
Filing Date:
April 03, 1996
Export Citation:
Assignee:
T. W. Incorporated
International Classes:
H03H11/04; H03H11/06; H03H11/10; H03H11/52; (IPC1-7): H03H11/04; H03H11/06; H03H11/52
Domestic Patent References:
| JP5368148A | ||||
| JP58111423A |
Other References:
ＩＥＥＥ ＭＴＴ−Ｓ ＩＮＴＥＲＮＡＴＩＯＮＡＬ ＭＩＣＲＯＷＡＶＥ ＳＹＭＰＯＳＩＵＭ ＤＩＧＥＳＴ，ｖｏｌ．２，２３−２７ ｊｕｎｅ １９９４，ＳＡＮ ＤＩＥＧＯ，ｐａｇｅｓ １１９１−１１９４，ＸＰ０００５１６７６１ ＫＡＲＡＣＡＯＧＬＵ ＥＴ ＡＬ．：”Ｈｉｇｈ Ｓｅｌｅｃｔｉｖｉｔｙ Ｖａｒａｃｔｏｒ−Ｔｕｎｅｄ ＭＭＩＣ Ｂａｎｄｐａｓｓ Ｆｉｌｔｅｒ Ｕｓｉｎｇ Ｌｏｓｓｌｅｓｓ Ａｃｔｉｖｅ Ｒｅｓｏｎａｔｏｒｓ”
Attorney, Agent or Firm:
Minoru Nakamura (6 outside)