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High CMRR Instrumentation Amplifier (Schematic and Layout) design for biomedical applications

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Instrumentation amplifiers are intended to be used whenever acquisition of a useful signal is difficult. IA’s must have extremely high input impedances because source impedances may be high and/or unbalanced. bias and offset currents are low and relatively stable so that the source impedance need not be constant. Balanced differential inputs are provided so that the signal source may be referenced to any reasonable level independent of the IA output load reference. Common mode rejection, a measure of input balance, is very high so that noise pickup and ground drops, characteristic of remote sensor applications, are minimized.Care is taken to provide high, well characterized stability of critical parameters under varying conditions, such as changing temperatures and supply voltages. Finally, all components that are critical to the performance of the IA are internal to the device. The precision of an IA is provided at the expense of flexibility. By committing to the one specific task of
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RF Probe Circuit

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A RF probe is a circuit of test equipment that converts a high frequency signal to a DC voltage. In this way it is very easy to measure RF voltages for either testing or adjustment transmitters, receivers, modulators.
The RF probe circuit described here is suitable for signals in the frequency range from about 100 kHz to 1000 MHz. Although the diode used here can, in principle, go up to 3 GHz, the impedance of the ground connection will adversely influence the measurement at such very high frequencies. Also, please keep in mind to use this probe only on low

RF Probe Circuit Diagram


Components list:
1 diode 1SS99
1 x 100p ceramic capacitor
1 x 10n ceramic capacitor
1 x 47K resistance
1 x small VU-meter

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