Ralph Stirling, KC3F, and I built the first generation using a Texas Instruments C5X DSK digital signal processing starter kit. Let it suffice to say that the second generation is a tremendous improvement over the first, because it uses a much more suitable DSP evaluation board from Motorola, the DSP56002EVM. You may wonder what the big deal is. Why are so many of the latest radios coming with DSP
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demodulators and filters Digital techniques have several advantages. Probably the most exciting is that everything is done in software. That means when I design a new demodulator you can download it to your radio and then you have my new demodulator. No soldering; no hunting parts; no ugly modifications; it`s so easy! Another benefit is that results are predictable. Component tolerances are not a factor as they are with analog signal processing. Simulations are easier to do and their results more closely approximate what happens in the actual system. Yet another advantage results from the speed of today`s DSPs. Nowadays it is quite realistic to have a digital filter with the equivalent of hundreds of poles, a filter that would require hundreds of inductors, capacitors or crystals in the analog world. Few analog designers use more than ten poles in a filter, because it`s very difficult to make designs with more work properly. This project actually started back in 1994. Ralph Stirling, KC3F, and I did exactly what Rick Campbell, KK7B, suggested in his original article on the R2 receiver. We used Rick`s R2 receiver and the Texas Instruments C5X DSK digital signal processing starter kit to construct a DSP based direct conversion receiver. We modified the DSK with our custom daughter board containing another TLC32040 codec. The DSP replaced the analog phase shift network with its digital counterpart and a sharp digital filter....
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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