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Type: Posts; User: shanmei

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1. ## Thread: input current of the integrator

by shanmei
Replies
15
Views
753

### Closed: Re: input current of the integrator

Sure, the feedback loop of force negative and positive node of the opamp to be equal.

Input current charges the negative node of the opamp, making it has a voltage rise, then the feedback loop...
2. ## Thread: input current of the integrator

by shanmei
Replies
15
Views
753

### Closed: Re: input current of the integrator

Thank you for all your feedback.

Why node Vx ( negative input node of the integator) does not change when the current charges Vx node, because it is is a low impedance node?

For an...
3. ## Thread: input current of the integrator

by shanmei
Replies
15
Views
753

### Closed: Re: input current of the integrator

Sorry I still do not understand.

Assume the input current is dc current, it can not go through the feedback capacitor as I1, and it can not go into the negative input node of the opamp ( the gate...
4. ## Thread: input current of the integrator

by shanmei
Replies
15
Views
753

### Closed: Re: input current of the integrator

Thank you for the feedback. Sure, a reset switch is needed to prevent saturation.

But during the integration process, how can the current "goes through" the feedback capacitor? For example, if we...
5. ## Thread: input current of the integrator

by shanmei
Replies
15
Views
753

### Closed: input current of the integrator

An integrator is built with an opamp and a feedback capacitor acossing the output node and negative input node of the opamp. The input current charges the negative input node, and the negative input...
6. ## Thread: sfdr simulation in Matlab

by shanmei
Replies
1
Views
276

### Closed: sfdr simulation in Matlab

I have a sine signal V1 with frequency 49.9MHz, and the sampling clock f1 with frequency is 110.6MHz. In Matlab, using sfdr(V1, f1), it brings the result as shown in Fig. 1. The fundamental signal is...
7. ## Thread: Energy harvest circuit questions

by shanmei
Replies
6
Views
450

### Closed: Energy harvest circuit questions

153913

I have several questions about energy harvest circuit as shown in the above figure.

1. How is the " radiation signal" in the air converts to the voltage or current signal along the...
8. ## Thread: transformer S11 simulation

by shanmei
Replies
2
Views
250

### Closed: transformer S11 simulation

I am building the transformer by using two inductors coupled with each other. Each inductor is a squred shape matal, and the two indcutors interweaving with each other.

by shanmei
Replies
10
Views
550

Thank you for all you reply. Yes, then I switched to the ADS EM simulation. It works for the coupling effect simulation.

It is weird that Cadence dose not provide good RF simulation enviroment.

by shanmei
Replies
10
Views
550

In Cadence, I want to simulate the two inductors placing very close. I don't know whether Cadence can simulate the coupling effect of the two inductors.

If...

by shanmei
Replies
10
Views
550

I have an inductor from cadence simulation. Can I export the S parameter from cadence and do the EM simulation in ADS? Thanks.
12. ## Thread: source pull simulation and input impedance match

by shanmei
Replies
9
Views
619

### Closed: Re: source pull simulation and input impedance match

The Zo in the red cycle is always there, and the blank space after it is not for entering the Zo. It is for the Zs or ZL input.

You can see...
13. ## Thread: source pull simulation and input impedance match

by shanmei
Replies
9
Views
619

### Closed: source pull simulation and input impedance match

Design one stage power ampifier. After doing the load pull and source pull simulation, I got the load and source impedance. Then I do the impedance matching for both the input and output of the...
14. ## Thread: A zero at folded cascode apmlifier

by shanmei
Replies
6
Views
1,036

### Closed: Re: A zero at folded cascode apmlifier

Wz is a zero location.

I didn't know what the zero location calculation can also use the gain-bandwidth constant relationship to obtain. Thanks.
15. ## Thread: A zero at folded cascode apmlifier

by shanmei
Replies
6
Views
1,036

### Closed: Re: A zero at folded cascode apmlifier

That's really helpful. Could you please explanate the zero? Why there is a zero and why the zero location is that? Thank you.
16. ## Thread: IC package company QFP80

by shanmei
Replies
1
Views
626

### Closed: IC package company QFP80

Is there any company can sell package QFP80? I never find it online. Thank you.
17. ## Thread: metal fill on the core circuit

by shanmei
Replies
2
Views
1,178

### Closed: metal fill on the core circuit

My chip is low frequency operation under 1MHz clock. For the layout, if the automatically metal fills on my core chip, whether it would influence the chip performance?

Usually I select the option...
18. ## Thread: A zero at folded cascode apmlifier

by shanmei
Replies
6
Views
1,036

### Closed: A zero at folded cascode apmlifier

Why there is a zero by counting the gain from the input to node2. Why the gain at high frequency is gm1/gm2? Thanks.

153070

page 10.
...
19. ## Thread: Resonant frequency sensing sensor

by shanmei
Replies
6
Views
1,702

### Closed: Re: Resonant frequency sensing sensor

The antenna is a senor that its resonant frequency would change in the range of 1GHz-5GHz. For example, if the environemnet pH value changes, the resonant frequency of...
20. ## Thread: Resonant frequency sensing sensor

by shanmei
Replies
6
Views
1,702

### Closed: Resonant frequency sensing sensor

Can the resonant frequency of different antennas being detected by a low-cost and simple method? Any sensor or chip? No VNA. Thanks.

by shanmei
Replies
4
Views
577

### Closed: Re: Voltage reading is not constant from DAQ

In the DAQ software setup, I set the terminal configuration to be " differential", then the measured signal is stable without the ripple.

152598

by shanmei
Replies
4
Views
577

### Closed: Re: Voltage reading is not constant from DAQ

Thanks you. When I connects it with the differential mode, when there is no ripple.

by shanmei
Replies
4
Views
577

### Closed: Voltage reading is not constant from DAQ

I have the NI6259 and want to read an analog signal.

I connect DC voltage 0.35V to the AI0 analog input pin of NI6259 through a BNC connector. The ground pin of the signal generator is connected...
24. ## Thread: LCC52 and LCC84 Eagle model

by shanmei
Replies
1
Views
330

### Closed: LCC52 and LCC84 Eagle model

Does anyone have the LCC52 and LCC84 model for the Eagle PCB layout? Thank you.
25. ## Thread: UHF RFID Chip impedance with 50 ohm

by shanmei
Replies
9
Views
1,480

### Closed: Re: UHF RFID Chip impedance with 50 ohm

20-j*200 is already the series equivalent circuit, and its impedance z=sqrt(20^2+200^2)=201 ohms.

-20dBm=0.01mW=0.00001

V=sqrt(2*P*R)=sqrt(2*0.00001*201)=63mV.

Should the V=sqrt(2*P*R) or...
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