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Type: Posts; User: mahdi3999

1. ## Thread: What technique can I use for this optimization problem?

by mahdi3999
Replies
0
Views
4,564

### Closed: What technique can I use for this optimization problem?

Hi,
I am new to genetic algorithms. I have studied only a few very simple examples to learn about the basics of GA. I would appreciate if anyone can give me some hints what technique I can use for...
2. ## Thread: Algo of cordic to find the resultant coordinate not giving desired results on matlab

by mahdi3999
Replies
1
Views
5,170

### Closed: Re: Algo of cordic to find the resultant coordinate not giving desired results on mat

I think you are making a mistake regarding the index of the q vector. For i=0 you have written a separate code using the if statement (this corresponds to the 45 degree angle). When the loop is...
3. ## Thread: Details of a CORDIC multiplier

by mahdi3999
Replies
6
Views
5,134

### Closed: Re: Details of a CORDIC multiplier

This is interesting. Have you seen any reference using this method?

By the way, I was making a mistake in my calculations, with the CORDIC multiplier, we only need to scale z0 to the appropriate...
4. ## Thread: Details of a CORDIC multiplier

by mahdi3999
Replies
6
Views
5,134

### Closed: Re: Details of a CORDIC multiplier

Hi CCNezin,

I can add this to your explanation that the CORDIC multiplier requires a sufficiently small z0 because after n iterations we have approximated z0 with a sum of powers of two. This...
5. ## Thread: Details of a CORDIC multiplier

by mahdi3999
Replies
6
Views
5,134

### Closed: Re: Details of a CORDIC multiplier

Hi CCNezin,

Your explanation seems quite reasonable but, with this explanation, we never need to set the initial value of y to zero (y0=0) neither we need to scale x0 and...
6. ## Thread: Details of a CORDIC multiplier

by mahdi3999
Replies
6
Views
5,134

### Closed: Details of a CORDIC multiplier

Hi,

I am looking for the details and proof of the CORDIC multiplier. I found a paper and a pdf which summarize the algorithms of the elementary functions but the linear mode of CORDIC is only...

by mahdi3999
Replies
1
Views
678

### Closed: Re: Gain of amplifier with current source load

Hi,
In the common-gate structure, the source voltage is determined by a voltage source, Vx. So, the transistor's gm will produce a current equal to gm * (0 - Vx). This current varies with Vx....
8. ## Thread: Piplelining for critical path delay

by mahdi3999
Replies
8
Views
1,393

### Closed: Re: Piplelining for critical path delay

You try to divide the critical path into M portions where each of these M portions have almost the same delay. In pipelining, you need to allow the combinational circuit between two successive...
9. ## Thread: Question in Poles in miller Capacitor

by mahdi3999
Replies
4
Views
998

### Closed: Re: Question in Poles in miller Capacitor

Assume that p1 and p2 are the roots of the denominator.
(s+p1)*(s+p2) = s^2 + (p1 + p2)*s + p1*p2

Multiply the above by b ( you can because the roots will not change) and equate with the...
10. ## Thread: Question in Poles in miller Capacitor

by mahdi3999
Replies
4
Views
998

### Closed: Re: Question in Poles in miller Capacitor

If you assume that the poles are -p1 and -p2 then p1+p2 = -a/b and p1 * p2 = 1/b. Since a Miller capacitor splits the poles, we can assume that one of the poles happens at a much higher frequency...
11. ## Thread: [moved] Explaination of Loop Filter for PLL

by mahdi3999
Replies
1
Views
438

### Closed: Re: [moved] Explaination of Loop Filter for PLL

Hi niteshtripathi,

If you apply an input current to the loop filter (current because the output of charge pump is current) and assume the voltage on the C2 as the output of the filter, then the...
12. ## Thread: 4-20mA signal conditioning

by mahdi3999
Replies
3
Views
828

### Closed: Re: 4-20mA signal conditioning

I think the DC bias of the op-amp is not correct. While you set the DC of terminal 3 to be zero, the DC of terminal 4 is set by that of the op-amp output. Terminals 3 and 4 must have the same DC...
13. ## Thread: implementation of a band-pass filter

by mahdi3999
Replies
30
Views
5,907

### Closed: Re: implementation of a band-pass filter

Pass band can be calculated from the desired center frequency and bandwidth.

The stop band, center frequency, bandwidth and the required attenuation at the pass band and stop band are all...
14. ## Thread: Help with results of a Wirelles Power Transfer Circuit.

by mahdi3999
Replies
2
Views
841

### Closed: Re: Help with results of a Wirelles Power Transfer Circuit.

Assume that you apply a current source Iin to a parallel RLC, at the resonant frequency, the voltage across the RLC will be Iin * R. The value of R affects the quality factor and the gain of the...
15. ## Thread: Higher order RC filter phase shift.

by mahdi3999
Replies
1
Views
573

### Closed: Re: Higher order RC filter phase shift.

You can calculate it just the way you calculate the phase response of any arbitrary transfer function (put j*omega instead of the s from Laplace transform, and calculate the phase). I think the only...
16. ## Thread: [Moved]: calculation of transconductance

by mahdi3999
Replies
3
Views
973

### Closed: Re: calculation of transconductance

Obviously the square law equation is suitable for hand calculations and can give us a rough approximation of the transistor's operating point. However, the complicated model involves several...
17. ## Thread: [Moved]: calculation of transconductance

by mahdi3999
Replies
3
Views
973

### Closed: Re: calculation of transconductance

I think you don't have to become involved in the complicated transistor models to find the transconductance of a transistor. Software can take all these parameters into account and give us the final...
18. ## Thread: Precise High Current Sensing at 12.5 mV/Amp

by mahdi3999
Replies
27
Views
5,455

### Closed: Re: Precise High Current Sensing at 12.5 mV/Amp

It seems that, putting the buffer in the first stage, you will not have a 10k load for the sensor, right?

Regarding the RC filter, if we only take the noise and linearity performance into...
19. ## Thread: Precise High Current Sensing at 12.5 mV/Amp

by mahdi3999
Replies
27
Views
5,455

### Closed: Re: Precise High Current Sensing at 12.5 mV/Amp

I think you will face a trade-off between linearity and noise performance: if you use the amplifier in the first stage, you will have better noise performance but since the...
20. ## Thread: implementation of a band-pass filter

by mahdi3999
Replies
30
Views
5,907

### Closed: Re: implementation of a band-pass filter

You can find some useful information here.

-Mahdi
21. ## Thread: Designing a symmetric FIR low pass filter

by mahdi3999
Replies
1
Views
1,230

### Closed: Re: Designing a symmetric FIR low pass filter

Calculate the inverse discrete-time Fourier transform of the target magnitude response. This will give you h_a[n]. Since you are asked to use a rectangular window with length 5, you only need to keep...
22. ## Thread: implementation of a band-pass filter

by mahdi3999
Replies
30
Views
5,907

### Closed: Re: implementation of a band-pass filter

First, you should determine what specs you are looking for, e.g. what's the center frequency of your filter, what's the -3dB frequency, etc.
Then, you can use either the classic filter design theory...
23. ## Thread: current mirror ratio V.S. noise

by mahdi3999
Replies
7
Views
1,658

### Closed: Re: current mirror ratio V.S. noise

Reducing the flicker noise requires a large W and L.
24. ## Thread: current mirror ratio V.S. noise

by mahdi3999
Replies
7
Views
1,658

### Closed: Re: current mirror ratio V.S. noise

You only need to place a capacitor between the gate and ground if you are using an nmos current mirror. For pmos current mirror put the capacitor between gate and vdd.
25. ## Thread: current mirror ratio V.S. noise

by mahdi3999
Replies
7
Views
1,658

### Closed: Re: current mirror ratio V.S. noise

Using a large capacitor at the gate of the transistors, you can bypass the noise from the diode connected device. So you only have to minimize the noise of the mirroring device which is related to...
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