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design a 65C02 based computer, but never got past the design stage. ), not in the field of teaching, so this page may come across as confusing in some places. I`d go with a 65C816, but I feel that for this project, something simple, and quick will do, even if I do have to pay more somewhere else for this "mistake". I`ll be modulating the voices with PCM, which means I`ll be sampling 8 bit audio at 8000 samples/second. The 65C02 will be able to apply the A/ µ law (dynamic range compression codec ) while it`s not sampling or resending data to the multiplexer. I`m hoping to run the CPU at 2 or 4 Mhz in order to be able to sample and retransmit information in a timely fashion and to be able to apply the "compression". I need to learn more about phone lines and impedance in order to fully understand what echo cancellation is, what wet transformers are and so forth, as this will be essential in determining how I am going to be interfacing DAC/ADCs to the phones. As anyone may know, a telephone line is composed of a long pair of copper wires (also called a twisted pair under some cases, when they are twisted around each other to avoid interference). Depending on the length, gauge and size of these wires, they respond differently to signals: impedance. In this case, we have to take into account complex impedance modelized as (resistance, Res; and reactance, Rea): Z = Res + jRea, where j is the "imaginary" number. In the case of...
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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