Search found 51 matches

by david753
Fri Jun 16, 2006 7:21 am
Forum: General Discussion
Topic: gambling machine, dices could be controlled
Replies: 8
Views: 1685

gambling machine, dices could be controlled

I repeat my question again. I have ever seen a gambling machine in casino when I was a child. This gambling machine is trick, dices result could be decided BEFORE throwing. It means the dices could be decided which side is up by computer, gambling machine. I have ever seen a special and accident sit...
by david753
Sun Jun 11, 2006 7:06 am
Forum: General Discussion
Topic: gambling machine, dices could be controlled
Replies: 8
Views: 1685

gambling machine, dices could be controlled

my question is "how to decide the value of dice after throwing".
I guess maybe there is magnet in the dice.

But, the dice has 6 faces.
How to use magnet to decide which dice toward upside?
by david753
Tue Jun 06, 2006 4:20 am
Forum: General Discussion
Topic: gambling machine, dices could be controlled
Replies: 8
Views: 1685

gambling machine, dices could be controlled

I have ever seen a gambling machine, that dices could be controled by the machine.
It means the machine could decide the result after throwing dices.
Do you know how it work?
How to make it?

Appreciated.
by david753
Fri May 06, 2005 3:30 pm
Forum: General Discussion
Topic: AWGN equation?
Replies: 0
Views: 486

AWGN equation?

I produce a signal equation of sinusoid with 8MHZ and 1Vp-p. Then, take it to DFT. I got the result, the peak is 4 dbm, noisefloor is about -170dbm in freqency domain. If I want to add some noise to input signal, upgrade the noise floor to -30dbm. What is the last equation of input signal? What is t...
by david753
Mon Apr 25, 2005 7:30 pm
Forum: General Discussion
Topic: Also introduce me, Mike
Replies: 2
Views: 518

Re: Also introduce me, Mike

Does your company have web site?
by david753
Mon Apr 11, 2005 7:59 am
Forum: General Discussion
Topic: fft coefficient and dbm?
Replies: 5
Views: 973

Re: fft coefficient and dbm?

FFT is easy to understand it, if we just see its theory formula.
But, if we want to implement to be a practical Instrument, it will have a little bit challenge. <p>Here is my problems that I encounter.
Check it out.
http://justfun.why3s.net/others/FFT2tone.doc
by david753
Tue Apr 05, 2005 12:58 pm
Forum: General Discussion
Topic: power supply circuit
Replies: 16
Views: 2716

Re: power supply circuit

http://ourworld.compuserve.com/homepages/Bill_Bowden/page4.htm#ps6.gif In this circuit, in second side, there are 2 sets output, but it is hard to buy it in market. Is it possible to buy a transform that only has 12.6, CT, -12.6 output? but, there will be 2 sets of ground in the system when switchi...
by david753
Fri Apr 01, 2005 12:11 pm
Forum: General Discussion
Topic: fft coefficient and dbm?
Replies: 5
Views: 973

Re: fft coefficient and dbm?

N=512; % point numbers f=11; fs=44000; %sampling freq. <p>t=0:N-1; q=1; for f=11:11:22000 % freq. varies y=sin(2*pi*f*t/fs); fy1=zeros(1,N/2); fy2=zeros(1,N/2); <p>for j=1:N/2 for i=1:N fy1(j)=fy1(j)+y(i)*cos(2*pi*j*i/N); fy2(j)=fy2(j)+y(i)*sin(2*pi*j*i/N); end end <p>fy_sum=sqrt(fy1.*fy1+fy2.*fy2);...
by david753
Tue Mar 22, 2005 12:22 pm
Forum: General Discussion
Topic: fft coefficient and dbm?
Replies: 5
Views: 973

fft coefficient and dbm?

I am implementing the Digital Fourier Transform now. After transfering, I got the coefficient of each of freqencies. But, I was confused what the relationship between the coefficient and dbm of real signal. For example, there is a signal with 2Vp-p amplitude and 10Hz input. The signal power is calcu...
by david753
Fri Mar 18, 2005 2:36 pm
Forum: General Discussion
Topic: power supply circuit
Replies: 16
Views: 2716

power supply circuit

Does anyone have power supply circuit that has 0~+/-30v dual output ports function and can be adjusted in voltage and current output?
I'd like to implement one that just for my hobby.
Please offer it as my reference.
Appreciated.
by david753
Sun Mar 13, 2005 1:41 pm
Forum: General Discussion
Topic: phase shift
Replies: 3
Views: 973

Re: phase shift

I want to make a phase shifter that can shift the phase 0-90 degree of PLL that role as a local oscillator.
I prefer the existen IC in the market.
by david753
Sat Mar 12, 2005 12:42 am
Forum: General Discussion
Topic: phase shift
Replies: 3
Views: 973

phase shift

I am looking for a phase shift component with 26mhz low pass filter that can shift its phase digitally.
It will be implemented in my receiver project.
Does anyone can give me idea?
by david753
Tue Feb 01, 2005 3:46 am
Forum: General Discussion
Topic: BPF design
Replies: 3
Views: 763

BPF design

I am going to design a BPF, the center is 26MHZ, span is 2MHZ.
After using ADS, I got the result at folling link.
http://homepage14.seed.net.tw/[email protected]/t0284754/26m.doc
But, I found the value of L2 is 9UF.
How can I make it?
which type core? and how many turns?
by david753
Sun Jan 23, 2005 6:45 am
Forum: General Discussion
Topic: Amplify, AD8367
Replies: 1
Views: 694

Amplify, AD8367

Dear fellows,
I got problems when I was implementing a component of AD8367.
Please refer to http://user52.starbeta.org/OTHERs/AD8367-agc.doc
Meanwhile, the circuit I implemented is resonating when the power is ON, and without any input signal.
by david753
Thu Jan 20, 2005 12:57 am
Forum: General Discussion
Topic: Questions about AD converter
Replies: 5
Views: 981

Re: Questions about AD converter

yes, you got.<p> <blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by cato:
Are you saying that you are using ac coupling as shown in Fig. 2 of the data sheet?<hr></blockquote>