公开(公告)号：JPH07202707A

公开(公告)日：1995-08-04

申请号：JP31635194

申请日：1994-12-20

Applicant: ADVANCED MICRO DEVICES INC

Inventor： KAARIN DOURUU KEIBURAA

IPC: H03M3/02

Abstract: PURPOSE: To provide a method for cascading two secondary sigma-delta modulators. CONSTITUTION: A method includes a step for sending an input to a quantizer 24 of a 1st stage to a 2nd state. Actually this input is the difference between the output of a 1st second-order loop and the quantization noise of a 1st modulater 18. The method further includes a step for eliminating the quantization noise outputted from the 1st loop and also eliminating an output of the 1st loop from a final output yout .

公开(公告)号：JPH07193506A

公开(公告)日：1995-07-28

申请号：JP26967194

申请日：1994-11-02

Applicant: ADVANCED MICRO DEVICES INC

Inventor： KAARIN DOURUU KEIBURAA

IPC: H03M3/02

Abstract: PURPOSE: To provide the method and system to realize A/D conversion of a high resolution. CONSTITUTION: The method for cascade connection of sigma-delta modulators includes a step where inputs E1 , E2 , and E3 of quantizers of modulator stages 12, 14, and 16 are sent to following stages. Consequently, signals sent to following stages are differences between outputs of preceding stages and a quantization noise. This method also includes a step where quantization noises of two first stages are eliminated in the same manner as outputs of two first stages to convert a final output yout of cascaded modulators to a delay version of input and, in addition, a scaled version of the last stage shaped by a fourth order high pass function.

公开(公告)号：JPH07321563A

公开(公告)日：1995-12-08

申请号：JP30886594

申请日：1994-12-13

Applicant: ADVANCED MICRO DEVICES INC

Inventor： KAARIN DOURUU KEIBURAA

IPC: H03F1/34 ,  H03F1/56 ,  H03F3/30

Abstract: PURPOSE: To provide an output stage having a low distortion. CONSTITUTION: A low distortion and low power output stage 300 includes a differential amplifier 310 instead of a source follower and a constant current source found in a conventional output stage. Voltage decrease is not present between the inversion differential input and non-inversion differential input of the amplifier 310, and the voltage decrease is not present between the input and output of the output stage 300. Thus, it is not necessary for a gain stage preceding to the output stage 300 to swing beyond output amplitude. Moreover, the amplifier 310 is provided with a common mode range capable of swinging almost between rails, and the output of the output stage is allowed to swing almost between the rails.

公开(公告)号：JPH0786951A

公开(公告)日：1995-03-31

申请号：JP20072794

申请日：1994-08-25

Applicant: ADVANCED MICRO DEVICES INC

Inventor： KAARIN DOURUU KEIBURAA

IPC: H03M1/08 ,  H03M3/02

Abstract: PURPOSE: To reduce the cost of pushing up noise to a high frequency and eliminating it by scaling the quantization error signals of preceding and succeeding modulators by the elements of mutual reciprocals, then connecting them and eliminating the quantization error of a preceding stage. CONSTITUTION: The modulators 24, 34 and 46 output outputs y1 , y2 and y3 for which the quantization error signals E1 , E2 and E3 are added to signals for which input delayed for 2 and 1 sample cycle is filtered by HPF function 1+Z 2 and 1 stage. The signals for which the signals E1 obtained by subtracting input signals from the output y1 are scaled by the element 32 and added to the modulator 34 and the signals E2 obtained by subtracting the signals E1 similarly are scaled by the element 32 and the element 44 equivalent to the reciprocal and added to the modulator 46. The respective outputs y1 , y2 and y3 are connected, the quantization errors E1 and E2 are eliminated and almost all noise is pushed up to the high frequency in a final stage. Thus, noise elimination is facilitated and a noise elimination cost is reduced.