74LS Voltage-controlled Oscillators. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of . Texas Instruments (TI) reserves the right to make changes to its products or to discontinue any semiconductor product or service without notice, and advises its . 74LS datasheet, 74LS circuit, 74LS data sheet: TI – VOLTAGE- CONTROLLED OSCILLATORS,alldatasheet, datasheet, Datasheet search site for.
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I think they have to work in conjunction with a phase detector. It would seem you could design one that works alone but the ones on the market require the phase detector.
If you could post your design for one it would be helpful. The datasheet tells you exactly what you ddatasheet and has circuits.
IC Datasheet: 74LS629
If you use a phase detector then you will also need a stable crystal oscillator for comparison. Then the circuit will be a single or switched frequency phase-locked-loop instead of a variable VCO. You can change the frequency of the VCO because the phase detector is programmed to reduce or increase the frequency produced by the crystal. Kevin, A phase detector produces a DC correction voltage to adjust the frequency and phase of the VCO so that it is exactly the same as the crystal oscillator.
You could put a switch-selected digital divider between the VCO and phase detector so that the VCO is an exact multiple of the crystal oscillator’s frequency. But since he said, “base frequency of 10KHz”, then maybe he isn’t allowed to do that.
I have seen frequency synthesizers that do the very same thing. They incorporate a phase detector, a programmable section, and a crystal.
IC Datasheet: 74LS : Free Download, Borrow, and Streaming : Internet Archive
What more is there to it. A frequency-synthesiser’s VCO jumps abruptly only to pre-determined frequencies, a VCO with a variable DC control voltage smoothly glides to any frequency within its range.
I understand what you are saying, but have you proven this? By the way I have seen the schematic for a VCO and it looks quite complicated. What you are looking for is here: Looks like the geniuses have let you down so far Hi MP, Thanks for the good demo of a 74LS that is used as part of a phase-locked-loop, whose VCO follows the exact frequency and phase of a variable clock oscillator. But the VCO’s frequency can simply be set with a DC voltage from a pot, then the clock oscillator and other parts aren’t needed.
74LS629 View Datasheet(PDF) – Texas Instruments
Dqtasheet Luzell, You didn’t ask for a phase-locked-loop, but please take your pick: Also note that I posted exactly what luzell asked for instead of telling him to try something else.
You might consider this sometime. There are times when students come onto the forum looking for help with an assignment they do not understand. Telling them to try something else is not at all helpful. Instead of the additional phase-locked-loop parts, you can use a simple variable DC control voltage from a pot that I recommended to dagasheet its frequency to 10KHz.
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74LS 데이터시트(PDF) – TI store
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