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Can inverters, like the ones found on 74LS04 ICs, operate like op-amps? I read somewhere that by connecting the output to the input, it can be made to function like an op-amp. If this is true, then the gain is equal to the feedback resistor value / input resistor value, assuming that that is all...
The reason i don't have filters for the harmonics on my transmitters is because i don't really care if the transmission has harmonics as long as i receive the fundamental.
because it is the closest to a sine wave that the oscillator could produce. The one I used are oscillators made up of inverters and crystals. It naturally would have provided a near square wave output but I adjusted the feedback a little and the closest to a square wave that I could get was a...
the receivers i use are quarter wave antennas and a half wave antenna, with a metal screen as the ground plane. they are 1 ft long and the ground plane is 1.3ft x 1.3ft. They are also connected to loading coils 0.25 ft from the feedpoint and are connected to RG6 for the half wave (75 ohms) and...
Hi,
So I built oscillators that produce near-triangle waves and I try to transmit them over a short distance of a few meters using several kinds of antennas. I use a half-wave and quarter wave antennas, although most of them are imperfect. I made 5 oscillators from 13MHz - 25MHz and they have...
i just figured out that i have no coax which has 50 ohms. all i have is a coax with 75 ohms. can i use this coax and connect it to the aerial? how much difference would it make compared to when i use a coax that has 50 ohms?
I tried tapping the scope directly to an antenna and it only got a bunch of frequencies according the FFT of the scope, I also tried adding a filter and tapping the oscilloscope across the filter and it did better, although some noise were still present, i was able to see on the FFT the...
well, i wouldn't be using any modulation actually. I would just like to send the produces waves across the room and at the receiver side it would just be a quarter wave monopole connected to probabaly a high pass filter then to an oscilloscope, just to see that i actually received it.
thank you. i will try that one tomorrow and hope it helps.
the thing is, is it, at all, possible? transmitting a triangle-ish wave (though it looks sine to me) which has around 3-4 harmonics at approximately 5 meters? is the 600mV enough to reach the receiver assuming all the losses in the...
hi,
i made some oscillators out of crystals and inverters and it turns out that the wave generated is close to a square wave. I used potentiometers for the feedback and adjusted it a little to get some sort of a traingle wave, although the wave looks sine to me and the oscilloscope gives me a...
So i decided to go back and check my oscillators using the 74LS04 inverters and found out that the output was actually closer to a triangle wave than a square wave. I also inspected the FFT and found out that it is indeed a triangle wave with 2-3 harmonics, the strongest of which is at most half...
and the LC tank should be tuned to the frequency of the crystal right? characterized by the equation:
f = 1 / (2*pi) * (sqrt(L*C))
following the equation and assuming that I have a fixed 10000nH / 10microH inductor, for a 25MHz oscillator, I should have a capacitor with a value of 4.05pF. I...
I just had an idea... so, i built an oscillator using inverters with the 74LS04 IC and it produces square waves as said by the oscilloscope although they appear to be sine waves. since the crystal acts as a filter for a specific frequency, what if I use the same crystal on a transistor...
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