The circuit is presented as a starting point - there will be some experimentation needed for each individual case. For the popular microwave bands the LOs are usually generated from overtone crystal oscillators followed by multipliers, with the following table showing the usual LO frequencies for the narrowband segments along with the associated crystal frequency. The final
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columns show the highest frequency that is a submultiple of both this and a 10MHz reference, the highest common factor or HCF, and the associated division. This HCF can become the comparison frequency in a phase locked loop, and is the highest frequency that is possible here. All the comparison frequencies can be derived from a 10MHz reference by making use of simple logic divider chips to give the divide by R function (all could be derived from 2MHz in fact) All the comparison frequencies are over 200kHz, so phase locked loops can be made with wide loop bandwidths. For those marked with a *, an even higher comparison frequency is possible, but the values stated keep the frequencies within a narrower band for a common design. So now the only difficulty is providing the divide by N from the crystal frequency. An off the shelf synthesiser chip such as the MC145170, or those from other manufacturers, would make an easy job of this but there is an even simpler solution providing you are prepared to do a bit more adjustment and optimisation. Anyone who has studied the brick` range of microwave sources will have seen how a high Q cavity oscillator is locked to a reference oscillator in the 100MHz region by a sampling phase detector. This device combines the functions of frequency multiplier and phase in one network. In the bricks, a snap varactor diode is hit with about 200mW of reference signal and so generates sharp...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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