zxl13
Junior Member level 2
I'm designing a 5.8G AGC system. use HMC346 as voltage control attenuator. When the input power change from -10 to 0dBm, I let HMC346 change from -14dB to -4dB loss. Now the output power can be controled in 1dB range.
But the problem is that HMC346 is a negative voltage control attenuator. When loss change from -14 to -4dB,the negative voltage change from -2V to -2.5V. So I use a voltage inverter AIC1660 to create negative volgate -5V and then use OP to do RF detect output voltage adjust and positive to negative.
Because voltage inverter AIC1660 has a fixed osc frequency 10kHz. It will be carried on the negative voltage and then input in the HMC346. Finally the RF output signal will carry this 10kHz modulation.
So any one can help me to solute this problem or is there any other solution to avoid this problem? (5.8G VCA I can only find HMC346)
But the problem is that HMC346 is a negative voltage control attenuator. When loss change from -14 to -4dB,the negative voltage change from -2V to -2.5V. So I use a voltage inverter AIC1660 to create negative volgate -5V and then use OP to do RF detect output voltage adjust and positive to negative.
Because voltage inverter AIC1660 has a fixed osc frequency 10kHz. It will be carried on the negative voltage and then input in the HMC346. Finally the RF output signal will carry this 10kHz modulation.
So any one can help me to solute this problem or is there any other solution to avoid this problem? (5.8G VCA I can only find HMC346)