O/PI modulator for 6 GHz signal, easy?

badaboum said:

Hello everybody,

first of all, i would like to thank you for reading this.
My, let's say, "problem" is very simple:
i would like to create a 0/PI modulator in order to modulate a RF signal (6GHz), that is to say, inverting the RF signal (+1 -1 like a ASK modulator) with a frequency between 500 Hz and 1 kHz.
1) Ok for creating the square wave generator (1 -1) with 500 Hz of repetition, if needed.
2) I've got the RF signal (6GHz)
3) and now...mixing...and that is my question. I don't really know how to choose the good design and which kind of component use:
- amplifier with G=1 and inverter amplifier with G=-1 driven (power on/off?) by the square wave, (not sure that is a good idea...)
- some transistors (FETs?) as switch driven by the square wave
- and otherwise, how can i realize the mixer? (schottky diode).

Click to expand...

jiripolivka said:

badaboum said:

Hello everybody,

first of all, i would like to thank you for reading this.
My, let's say, "problem" is very simple:
i would like to create a 0/PI modulator in order to modulate a RF signal (6GHz), that is to say, inverting the RF signal (+1 -1 like a ASK modulator) with a frequency between 500 Hz and 1 kHz.
1) Ok for creating the square wave generator (1 -1) with 500 Hz of repetition, if needed.
2) I've got the RF signal (6GHz)
3) and now...mixing...and that is my question. I don't really know how to choose the good design and which kind of component use:
- amplifier with G=1 and inverter amplifier with G=-1 driven (power on/off?) by the square wave, (not sure that is a good idea...)
- some transistors (FETs?) as switch driven by the square wave
- and otherwise, how can i realize the mixer? (schottky diode).






One way to modulate your 6 GHz signal is to use two PIN switches and insert one and three-quarter wave line sections , one after another, by the modulation signal. There are such phase modulators available as MMICs, see "www.hittite.com".
Usig mixers is also possible, I-Q mixers are also available as MMICs at Hittite. Lower-cost devices are available at "www.minicircuits.com".

Click to expand...

Hi, thank you for this reply. Indeed, I was thinking of using IQ modulators but there are some internal amplifiers at the RF input in order to saturate the mixing signal and thus obtaining a good IQ modulated signal at the output. This is a problem for me because i want to keep the envelope of the RF signal (that is to say obtaining a ASK modulated signal but with the envelope of the RF signal). So, as you said, if i find a IQ mixer (1-6 GHz) without any internal amplifier, it could work....

Click to expand...