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digitalblggr
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Is it better to use an op-amp oscillator or a crystal oscillator to produce 40 Khz sine wave?
Doesn't anyone make a simple chip for this sort of thing?
Studiot said:For mass production these days it is simple (and cheap) to use digital frequency synthesis which is why the 8038 and XR2206 went out of production.
Okefenokee said:Yeah, but not everything is about mass production. What about hobbyists and developers? A small breakout board with an output which could be tuned from 10Hz to 100kHz would invaluable. One could design something that could be tuned by adding highly accurate resistors or capacitors.
vk6kro said:Actually he is asking for a sinewave output, vk6kro.
As I mentioned, pin 1 of that chip will have a sinewave on it.
Phrak said:I read that as '1 pin'. I'm not at all clear how stable the amplitude of any given crystal, or variation in amplitude over a part numbers is from a driven crystal. Do you know anything about that?
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A pic is fairy easy to program. An output driven as a pwm and combined with an operational amplifier and some multiple of 40 KHz oscillator oscillator will give a clean stable source.
vk6kro said:I have used this circuit as a local oscillator for receivers (although not at 40 KHz).
The input to a CMOS gate is very high impedance, so you have to take the output to some device that is also high impedance. To maintain the sinewave, this would probably mean a FET either as a source follower or a common source amplifier.
A I recall, the sinewave here could be very clean looking on an oscilloscope, although this may not always be the case, I guess.
The signal level is large (several volts p-p) and absolutely steady as long as the load does not vary. And, you can't match the precision and frequency stability of crystal control.
An op-amp, or operational amplifier, is an electronic component that amplifies the difference between two input signals. It is commonly used in electronic circuits to perform mathematical operations such as addition, subtraction, and integration.
A crystal oscillator is an electronic circuit that uses the mechanical resonance of a vibrating crystal to generate an electrical signal with a precise frequency. It is commonly used as a timekeeping device in watches and clocks, and in electronic circuits as a stable frequency reference.
An op-amp is used to amplify an input signal, while a crystal oscillator is used to generate a precise frequency. While an op-amp can be used to amplify a wide range of frequencies, a crystal oscillator is designed to generate a specific frequency, such as 40kHz in this case.
A crystal oscillator is better for generating a 40kHz sine wave, as it is specifically designed to produce a precise frequency. An op-amp may introduce distortions and variations in the frequency, making it less suitable for this purpose.
While an op-amp can be used to generate a 40kHz sine wave, it may not be as accurate or stable as a crystal oscillator. Additionally, it may require additional components and adjustments to achieve the desired frequency, making it more complex and potentially less reliable compared to a crystal oscillator.