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4-channel data telemetry system schematic detailed descripti

2014-12-18 21:11  
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This article is a 4-channel data telemetry system theory in detail. Figure combining text to understand this principle is a very good choice. The 4-channel data telemetry data transmission system via different types of sensors. They include temperature sensors, fuel level sensors, pressure sensors, and speed sensors. All of these sensors have analog output voltage of the form, so we must put it into digital data and then we will be able to transfer. Four different types of data are transmitted trough a multiplexer channels so require. Because of this we use the word multiplexer switches, four data and converting it into digital form one by one. Note: Transmitter Range 12 - 15 feet of data transmission block diagram shows the data transfer message signal through some modulation process.

 

image 1 4 channel data telemetry system

 

image 2 4 channel data telemetry system

 

Data Receiving

image 3 4 channel data telemetry system

After receiving Data from receiver, it will be demodulate after the process of demodulation we will get the real data which we required and we want to transmit and we can easily display it. Note: Transmitter Works on 98 MHz

Function Block Diagram

image 4 4 channel data telemetry system

Circuit Diagram
schematic th 4 channel data telemetry system
image 5 4 channel data telemetry system
 

image 6 4 channel data telemetry system

 

image 7 4 channel data telemetry system

The circuit is a  M4066  analog and digital switching, three or four input / output pin which has a control signal to control the data flow circuitry. This is controlled by the microcontroller port pin with 2.1 - 2.4. With all of these signals are analog signals, so we must be converted into digital data is referred to the analog to digital converter converter ADC. To do this we use the IC ADC0804. This digital equivalent of the analog signal. The main thing is, why do we analog to digital converter?? Because we have three sensors, so we must multiplex transmission of these signals is required, and this is a complete digital signal multiplexing is essential to use this species due to the analog-digital converter. 8 output digital signals into controller port 1.0 - 1.7. In the data entry microcontroller through the transmitter. This is the final part of the circuit. Another part of the circuit where the transmission section. Let explore this part of the circuit. We have some of this signal transmission adjusting its distance signal transmission. Good modulation circuit is built in the transmitter circuit. Here we use frequency modulation, the main aspect is that the frequency modulation is easier to use can be transmitted by the distance to our request, which is nearly two kilometers. So the radio frequency FM are widely used for data transmission. This transmission signal in the transmitter 102 MHz.

image 8 4 channel data telemetry system

Data Flow Diagram
image 5 4 channel data telemetry system
Data Sheet
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Calculations for downlink

Free space path loss at distance 2km is 78.285dB

Frequency 98 MHz

Effective Isotropic radiated Power is 9dB

Antenna gain is 10

radiated power is 0.8W