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200MHz400MHz VOLTAGE CONTROLLED OSCILLATOR
If you need a clean emitter coupled logic (ECL) type signal between 200MHz
and 400MHz this circuit works fine. It uses four voltage-controlled
capacitors to change the frequency.
CMOS
INVERTER 125KHz LC OSCILLATOR
This circuit uses a single CMOS inverter to form a series resonant LD
oscillator. The values shown set the oscillation at about
125KHz but other frequencies are possible by changing the main LC values.
CMOS INVERTERS FORM
125KHZ OSCILLATOR
This circuit is similar to schematic CMOS INVERTER
125KHz LC OSCILLATOR but inverts the LC components so the inductor is grounded.
Two inverters are needed to produce the needed oscillation. Again, the values
shown set the frequency at 125KHz but can be changed to produce other frequencies.
CMOS
INVERTER PARALLEL LC OSCILLATOR
I have used this parallel resonant LC oscillator circuit countless times. The
oscillator frequency is determined by the inductor and capacitor values. I
have shown an adjustable inductor to make it easy to set the frequency to a specific
value. Once set the frequency is fairly stable over supply voltage variations
and temperature changes. The values shown are for 125KHz but the frequency can
range from tens of kilohertz to tens of megahertz. With a 74HCU04 type
inverter, it will oscillate down to about 1.5 volts. If the frequency is low,
you can also use a 74C04 (CD4069) inverter.
CMOS
SCHMITT TRIGGER IC MAKES VCO
By changing the supply voltage fed to a classic 4584 Schmitt trigger type
oscillator, the oscillator frequency can be changed over a range of 50:1. A
74HCU04 inverter is used at the output of the 4584 to maintain a constant TTL logic
level signal.