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Recent content by nwo4life

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    HELP!!! ANALOG GND Vs DIGITAL GND

    привод analog gnd hey, You must separate your analog and digital GND's. If you can shield your analog circuits and GND from your digital circuits. Why? Well since your digital circuits are always switching, this creates noise and fluctuations in your power and ground rails. So there...
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    74LS90 divide by 5 problem

    Hi, I am using the 74LS90 counter to divide a frequency by 5. However, the output of the 74LS90 is not symmetrical. Instead it produces pulses every 5 counts (clock cycles). My connection is as follows, PIN 1: CP1_bar --> this is my input PIN 2: MR1 --> connected to ground PIN 3: MR2 -->...
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    LM565: reducing loop gain

    Hi, I am using the LM565 PLL with power supply of 5V (ie. Vcc = 5V, -Vcc = -5V). However this means that most likely my loop gain(KoKd) will be greater then the inverse of the timing capacitor(Co) and resistor(Ro). The data sheet says that...
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    555 timer with a multiplexer(MUX)

    Hi, I am using two 555 timers to generate two different frequencies. They work great. However, I want to use the 74LS157 2 to 1 MUX to control which frequency goes through. When i connect the two out puts of the 555 timers to the inputs of the MUX i get strange waveforms out. My select...
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    IC question (unused pins)

    Hi, I am using a 74LS157 (Quad 2 to 1 multiplexer). However I only need to use one of 2 to 1 multiplexer. My question is, should I ground the pins I don't use or leave them alone. Thanks
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    Need help with using the virtual PLL in Multisim

    pll con multisim The details of my circuit are as follows: 1.) It is a digital frequency multiplier (times 5). I am using the 74LS90 decade counter as my divide by 5 block. 2.) My input range is from 500Hz to 2kHz. 3.) I am using a LM565 PLL IC.
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    Need help with using the virtual PLL in Multisim

    Hi, Does anyone have any experience using the virtual PLL in Multisim? I need help using (ie. selecting free running frequency, cutoff frequency of lowpass filter, etc.). Also can the virtual PLL be used with clocking signals (digital)? THANKS
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    555 Timer Help needed

    To ahmad_abdulghany Would you be able to give more detail on your second idea. THANKS
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    555 Timer Help needed

    switching an npn transistor with a 555 timer Hi, I need to make an FSK (frequency shift keying) generator using the 555 timer. My marks are as follows, '0' = 1000 Hz '1' = 1200 Hz I have calualeted all the resistor and capacitor values for both frequencies, but I don't know how to...
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    MATLAB lpc command (linear Prediction)

    linear prediction in matlab anyone have any hints.
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    PLL Frequency Multiplier

    Yes I have looked a the data sheet but I still don't understand how to get the values of the previously mentioned variables.
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    PLL Frequency Multiplier

    Hi, I am using the LM565 PLL and a 74LS90 decade counter to design a times 5 frequency multiplier. I have figured out how to use the counter but I am having trouble with the LM565 PLL. My multiplier should work from (input range) 500Hz to 2kHz (ie. my outout range is therefore from 2.5kHz to...
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    MATLAB lpc command (linear Prediction)

    linear prediction matlab Hi, I was wondering how do you get the spectrum of the lpc (linear prediction). I did the following: a = lpc(x,10); A = fft(a); plot(abs(A)); Is this right? Also I choose the model order as 10 just as a starting point, my final model order will be when the lpc...
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    Lock in range of 565 pll

    565 pll Anyone have any hints.
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    Lock in range of 565 pll

    pll 565 Hi, I am designing a frequency multiplier (five times) with the LM565 PLL. My input range is from 500Hz to 2000Hz, which means my output range is 2500Hz to 10000Hz. From what I know the free running frequency should be in the center of the range. Now should that center be between 500Hz...
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