I'm sure you're already familiar with AM and FM radios, and perhaps even some other types such as phase modulation. They all have modulation in common though.
The only reason for this, however, is to make the signal's frequency high enough to transmit on a reasonably sized antenna.
I figured though, why not do that without modulation? Doing so would make for a simple, and probably cheap radio. Here's a block diagram of the design I thought of:
This particular one is set up for half duplex. The controls in square boxes are all ganged together, while the controls in circles are independent. The transmit side is on the left and the receive side is on the right. They share power supplies and the antenna. The audio signal itself is the only thing transmitted, after it is multiplied in frequency and increased in amplitude. A frequency divider on the receiver reverses the process to reproduce the audio.
The only component shown that is not pretty much standard is the variable frequency multiplier. I'm not sure exactly how one would design it, but I have an idea that would use one chip and six multipliers to give several channels. Each channel would have to only be divisible by 1, 2, or 3. (Channels: 1, 2, 3, 4, 6, 8, 12, 18, 27). The chip would take the input from a dial, and use it to decide which frequency multiplier(s) to run the signal through.
I know my little diagram is hard to read, just ask about it if something isn't clear.
What do you think? Would it work? Would it be any better than existing models in any way?
The only reason for this, however, is to make the signal's frequency high enough to transmit on a reasonably sized antenna.
I figured though, why not do that without modulation? Doing so would make for a simple, and probably cheap radio. Here's a block diagram of the design I thought of:
This particular one is set up for half duplex. The controls in square boxes are all ganged together, while the controls in circles are independent. The transmit side is on the left and the receive side is on the right. They share power supplies and the antenna. The audio signal itself is the only thing transmitted, after it is multiplied in frequency and increased in amplitude. A frequency divider on the receiver reverses the process to reproduce the audio.
The only component shown that is not pretty much standard is the variable frequency multiplier. I'm not sure exactly how one would design it, but I have an idea that would use one chip and six multipliers to give several channels. Each channel would have to only be divisible by 1, 2, or 3. (Channels: 1, 2, 3, 4, 6, 8, 12, 18, 27). The chip would take the input from a dial, and use it to decide which frequency multiplier(s) to run the signal through.
I know my little diagram is hard to read, just ask about it if something isn't clear.
What do you think? Would it work? Would it be any better than existing models in any way?
