Hi Folks
am trying to build a sensor system. It consists of capacitive sensors (20 nF) which change capacitance when they sense a particular substance.
To measure this change in capacitance I am using them as part of a Twin T oscillator network, so that when the capacitance changes, the oscillator frequency also changes. I now need to build a circuit to measure the frequency change.
I am not able to attach an image of the system that I am building. However, I'll try to explain. Could I use the following set up to detect the frequency change.
Twin T oscillator ---------->Phase detector------>Low pass filter----> Voltage out
I I
I I
Freq. out <------------------VCO-----------------------------
Could this be achieved straight using a PLL IC.
Please send me all the inputs. I would really appreciate if you could send me a block diagram of the circuit that I would need. In case you are unable to send it through this, you could email it to me at bhatshreyas@gmail.com
Thanks
Shreyas
am trying to build a sensor system. It consists of capacitive sensors (20 nF) which change capacitance when they sense a particular substance.
To measure this change in capacitance I am using them as part of a Twin T oscillator network, so that when the capacitance changes, the oscillator frequency also changes. I now need to build a circuit to measure the frequency change.
I am not able to attach an image of the system that I am building. However, I'll try to explain. Could I use the following set up to detect the frequency change.
Twin T oscillator ---------->Phase detector------>Low pass filter----> Voltage out
I I
I I
Freq. out <------------------VCO-----------------------------
Could this be achieved straight using a PLL IC.
Please send me all the inputs. I would really appreciate if you could send me a block diagram of the circuit that I would need. In case you are unable to send it through this, you could email it to me at bhatshreyas@gmail.com
Thanks
Shreyas