Signal Modulation using IC MC1496

Thread Starter

datdang

Joined Feb 21, 2023
27
Hi everyone,
I want to use IC MC1496 to modulate three analog signal X, Y, Z from accelerometer sensor so I can transmit all of these three analog signals in one Wire. At the receiver, I will use IC MC1496 to demodulate and separate these signals . I just attach the modulation circuit diagram using IC MC1496, but It seems hard to understand this circuit . If anyone have any experience in designing this circuit , please help me, thank so much .
 

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Ian0

Joined Aug 7, 2020
9,436
How do you propose to modulate the signals? I can't imagine that with amplitude modulation you are going to read the signals with any degree of accuracy.
It's not a technique anyone would use these days - it would be sent digitally, or, maybe by time-division multiplexing. In the past, when electronics were expensive and copper was cheap, one would have just used 3 cables.
 

DickCappels

Joined Aug 21, 2008
10,120
The MC-1496 is a great little chip for amplitude modulation or double side and generation, which is what the. It is not a good solution for transmitting three data streams.

You could do it with three of them and use frequency division multiplexing so you can sort them out at the receiving end but that would require a lot of parts and some tuning would be needed.

Are you interested in a digital approach?

In the meantime please explain the
X, Y, and Z signals and the relationships among them if there are any such relationships.
 

crutschow

Joined Mar 14, 2008
33,977
I assume you plan on using three separate modulators operating at three distinctly different carrier frequencies.
The receiving end will then need three filters to separate the three carrier frequencies along with three demodulators.
You need to carefully select the three carrier frequencies to avoid harmonics that can cause heterodyning and signal crosstalk.

All of that involves a lot of analog circuitry.
A/D converting each signal, and then sending the three signals in a time-division multiplexing scheme is likely a better way to go.

What are you doing with the recovered signals at the receiving end?
 

Thread Starter

datdang

Joined Feb 21, 2023
27
How do you propose to modulate the signals? I can't imagine that with amplitude modulation you are going to read the signals with any degree of accuracy.
It's not a technique anyone would use these days - it would be sent digitally, or, maybe by time-division multiplexing. In the past, when electronics were expensive and copper was cheap, one would have just used 3 cables.
The best is to digitalize these signal and modulate it , can you suggest which MCU I should use to ADC these signal and which MCU I should use to modulate it , sorry but I have a little experience in this field
 

Thread Starter

datdang

Joined Feb 21, 2023
27
I assume you plan on using three separate modulators operating at three distinctly different carrier frequencies.
The receiving end will then need three filters to separate the three carrier frequencies along with three demodulators.
You need to carefully select the three carrier frequencies to avoid harmonics that can cause heterodyning and signal crosstalk.

All of that involves a lot of analog circuitry.
A/D converting each signal, and then sending the three signals in a time-division multiplexing scheme is likely a better way to go.

What are you doing with the recovered signals at the receiving end?
I think I should convert these signals into digital signals ,that would be the best to transmit . At the receving end I plan to use these signal to calculate Inclination of Oil- Well. These transmit will be transmitted through 6-7 km Cable to reach the sufface receiver .
 

Thread Starter

datdang

Joined Feb 21, 2023
27
I think I should convert these signals into digital signals ,that would be the best to transmit . At the receving end I plan to use these signal to calculate Inclination of Oil- Well. These transmit will be transmitted through 6-7 km Cable to reach the sufface receiver .
The MC-1496 is a great little chip for amplitude modulation or double side and generation, which is what the. It is not a good solution for transmitting three data streams.

You could do it with three of them and use frequency division multiplexing so you can sort them out at the receiving end but that would require a lot of parts and some tuning would be needed.

Are you interested in a digital approach?

In the meantime please explain the
X, Y, and Z signals and the relationships among them if there are any such relationships.
Yes, I'm interested in a digital approach but I have a little experience in digital transmit, I know we can use DSPic33F to convert Analog to digital but to modulate digital signal I have no experience. X,Y,Z signals are from Accelerometer sensor ADXL 354/355. At the receiver, I will combine all of these signal and use a special formula to get the inclination of object
 

crutschow

Joined Mar 14, 2008
33,977
I have no experience in specific microprocessors to recommend a specific one, but I would expect there are models of the Arduino that can digitize the three low-frequency signals, and send the digital words in packets, using a serial data format such as SCI or SPI, to a receiving Arduino for recovery.
 

djsfantasi

Joined Apr 11, 2010
9,151
To recommend a microprocessor, you’d need to supply more information. What do you have to power it? Are there any size restrictions?

Plus, there are many different ways of sending digital data. Just off the top of my head, I can think of seven.

What’s your programming background? That constrains the selections significantly.

I’m very familiar with the Arduino platform. If I had the space, I’d use an Arduino Uno. It has significant ADC pins for your three channels. Plus it can easily add add-on boards (“shields”) if you need them. However 6-9 meters could probably be fine for the onboard serial connection. And the Arduino supports libraries that simplify programming. It starts as simple as using the command Serial.print() to send the data and Serial.read() to read the data. However simple I have made that, there are details that need to be addressed.
 

Ian0

Joined Aug 7, 2020
9,436
I think I should convert these signals into digital signals ,that would be the best to transmit . At the receving end I plan to use these signal to calculate Inclination of Oil- Well. These transmit will be transmitted through 6-7 km Cable to reach the sufface receiver .
RS485 will manage 1200m at 100kbit/s, which suggests it might manage 20kbit/s over 6km. As I doubt you need the readings in a hurry, you could slow the data rate down even further. A telephone twisted pair can send audio over >10km which a bandwidth of 3.4kHz.
Almost any microcontroller will have some A/D converters and a UART to send the data.

If the sender can be battery powered, you could send the data over fibre-optics.
 

Thread Starter

datdang

Joined Feb 21, 2023
27
To recommend a microprocessor, you’d need to supply more information. What do you have to power it? Are there any size restrictions?

Plus, there are many different ways of sending digital data. Just off the top of my head, I can think of seven.

What’s your programming background? That constrains the selections significantly.

I’m very familiar with the Arduino platform. If I had the space, I’d use an Arduino Uno. It has significant ADC pins for your three channels. Plus it can easily add add-on boards (“shields”) if you need them. However 6-9 meters could probably be fine for the onboard serial connection. And the Arduino supports libraries that simplify programming. It starts as simple as using the command Serial.print() to send the data and Serial.read() to read the data. However simple I have made that, there are details that need to be addressed.
The problem with Arduino is that It can not sustain high temperature. I'm planning to use this circuit inside an Oil-well which normally has high temperature above 100 degree , DSPic33F for ADC could sustain high temperature up to 125 degree. But How can I modulate digital signal , could you suggest any MCU to modulate digital signal
 
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