Signal receiving circuit and digital signal processing system

United States Patent [w]

Kanazawa et al.

US005880601A [ii] Patent Number: [45] Date of Patent:

5,880,601 Mar. 9, 1999

[54] SIGNAL RECEIVING CIRCUIT AND

DIGITAL SIGNAL PROCESSING SYSTEM

[75] Inventors: Nobuaki Kanazawa; Masao Mizukami, both of Yokohama; Kunihiro Ito, Ome, all of Japan

[73] Assignees: Hitachi, Ltd., Tokyo; Hitachi Communication Systems, Inc.,

Kanagawa, both of Japan

[21] Appl. No.: 750,581

[22] PCT Filed: May 25, 1995

[86] PCT No.: PCT/JP95/01001

§ 371 Date: Feb. 27, 1997

§ 102(e) Date: Feb. 27, 1997 [87] PCT Pub. No.: W095/34954

PCT Pub. Date: Dec. 21, 1995 [30] Foreign Application Priority Data Jun. 13, 1994 [JP] Japan 6-154169

[51] Int. CI.6 H03K 19/094

[52] U.S. CI 326/68; 326/73; 326/71

[58] Field of Search 326/70, 71, 73,

326/74, 68, 83

[56] References Cited

U.S. PATENT DOCUMENTS

5,204,557 4/1993 Nguyen 326/68

5,486,785 1/1996 Blankenship 326/68

5,617,045 4/1997 Asahina 326/68

5,698,993 12/1997 Chow 326/81

5,781,026 6/1998 Chow 326/68

Primary Examiner—Michael Tokar

Assistant Examiner—Richard Roseen

Attorney, Agent, or Firm—Fay,Sharpe,Beall,Fagan,Minnich

& McKee

[57] ABSTRACT

A signal receiving circuit comprising a first P-channel MOSFET amplifier and a first N-channel MOSFET amplifier having gates supplied with positive signals from a pair of signal transmission lines; and a second P-channel MOSFET amplifier and a second N-channel MOSFET amplifier having gates supplied with negative signals from said pair of signal transmission lines; wherein a first output signal is formed by so adjusting the gains of the first P-channel MOSFET amplifier and of the second N-channel MOSFET amplifier that the resultant signals have an intermediate amplitude between the operation voltages, and a second output signal is formed by so adjusting the gains of the second P-channel MOSFET amplifier and of the first N-channel MOSFET amplifier that the resultant signals have an intermediate amplitude between the operation voltages. This makes it possible to receive various small signals lying over a wide range even by using a sense amplifier which has only a fixed operation range in the signal receiving circuit as well as to constitute a novel and optimum system by combining semiconductor integrated circuit devices having different low-amplitude interfaces.

6 Claims, 5 Drawing Sheets