This oscillator is a variation of the oscillator presented by Ulrich L. Rohde, DJ2LR, in his article `Evaluating Noise Sideband Performance in Oscillators`, Ham Radio, October 1978, Page 51. The original circuit is at the bottom of the web page `4 MHz Oscillator` in the Super Receiver section of this web site. The article states the above oscilla
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tor is a "suitable low-noise crystal oscillator circuit with a wideband postamplifier that delivers the required +17 dBm output level or slightly more. Any inductive-mode crystal between 400 KHz and 30 MHz can be plugged into this circuit and give useful output without any adjustments. " "The noise performance of the crystal oscillator circuits. is better than 120 dB/Hz at 1 KHz from the carrier, and 150 dB/Hz or more at 20 KHz from the carrier. Because of their excellent noise performance, these circuits can be used as local oscillators without degrading receiver performance; very few oscillators and practically no frequency synthesizers achieve their low-noise sideband levels. " Update: Email correspondence with Dr. Rohde (April 2008) shows that even better performance is now available. Dr. Rohde wrote that ". at 5 MHz my oscillator with a 2008 quality crystal, Q=2. 6 E6, Cs=8ff, and some modifications gives a superb phase noise. " See curve below, much better noise now. Diode switching is used to switch the crystal frequency. Regular LEDs were found to work just as well as 1N914s, used in almost every crystal switching circuit in Ham radio literature. The advantage of using LEDs is the visual indication of which oscillator is on, helping with diagnosis in case the switching circuit is not operating properly, or in the case of this receiver, ambient light is interfering with the proper operation of the phototransistor....
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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