Make Z3801A GPS-disciplined oscillators more useful by making 1 PPS and additional 10MHz signals available on the rear panel, and providing a 1 PPS signal on the DCD line of the serial connector so the unit could serve as a reference clock for an NTP server. Although I ultimately want to add a distribution amplifier/splitter for the 10MHz sine wave signal, I thought it would be easier to initially add several
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10MHz TTL square wave outputs. This page describes how I did that. Jeff Mock has published a modification that provides a nice RS-232 level 1 PPS signal on the DCD line, so I used that as the starting point. (Note: I`ve learned that Jeff`s web page is no longer there. A mirror is at. ) Jeff taps a 1 PPS TTL level signal off of U5, pin 2 (a Lucent 1141LL, whatever that is). I used that signal to drive my 1 PPS circuit. After probing around on the board, I was unable to discover a 10MHz TTL level square wave anywhere. However, TP5 in the front portion of the main board has a nice 10MHZ sine wave available, which unfortunately is riding on top of a DC bias voltage. I used a piece of RG-174 cable to bring the signal from TP5 back to my circuit. The front pin of the adjacent TP4 complex is at ground, so I connected the RG-174 shield there. The 1 PPS circuit is very simple. I used a 74AC04 hex inverter, with the first section providing an initial inversion so that the end result remains a positive-going pulse. The output is a pair of inverters parallelled together through 51 ohm resistors; this combination provides a nice low-impedance signal that can drive a reasonable length of coax. The unused sections of the 74AC04 must be tied to something; if they float, the chip may oscillate or otherwise find itself in a state of high current draw. I tied the unused inputs to the output of the first inverter, so they are available as...
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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