Hi guys,
I'm not sure if you have heard of DCF77, but I need to create a simple DCF77 generator which is basically a 77.5kHz carrier that has 1 bit a second encoded into the carrier. It is lowered to 20% of the amplitude for either 0.1 or 0.2 seconds at the start of each second depending on whether the bit for that second is a 0 or a 1.
I have tried using a simple voltage divider network such as the one below, but with a transistor and resister in parallel with the second resistor which would control the amplitude. However I am getting a weird waveform.. the negative side of the sine wave does not have the same amplitude as the positive side.
I would like to know if anyone has had any similar experiences with this kind of modulation scheme and see if anyone has any suggestions.
Thanks in advance
Bruzzac
I'm not sure if you have heard of DCF77, but I need to create a simple DCF77 generator which is basically a 77.5kHz carrier that has 1 bit a second encoded into the carrier. It is lowered to 20% of the amplitude for either 0.1 or 0.2 seconds at the start of each second depending on whether the bit for that second is a 0 or a 1.
I have tried using a simple voltage divider network such as the one below, but with a transistor and resister in parallel with the second resistor which would control the amplitude. However I am getting a weird waveform.. the negative side of the sine wave does not have the same amplitude as the positive side.
Rich (BB code):
---/\/\/\/\-------/\/\/\/\-------
Rich (BB code):
I would like to know if anyone has had any similar experiences with this kind of modulation scheme and see if anyone has any suggestions.
Thanks in advance
Bruzzac