Understanding Analog Division

Analog division involves generating an output signal that is proportional to the ratio of two input signals. One common method of achieving this operation is the use of logarithmic and antilogarithmic amplifiers. By using the basic logarithmic properties, we can easily perform the multiplication and division of two signals.

The the output to input ratio can be adjusted by the help of additional input acting as the scaling factor for the process.

Designing the Analog Divider

To build an analog divider with operational amplifiers (OP-amps), the fundamental concept is to utilize them as log and anti-log amplifiers. This involves taking the logarithm of the Numerator, Denominator, and Scaling factor inputs, then adding the Scaling factor to the numerator and subtracting the denominator to achieve the division with the intended output-to-input ratio. Finally, the antilogarithm of the result is taken to obtain the desired output.

The circuit design involves the following stages:

1.     Logarithmic Amplification of the inputs:

This stage converts the input signals into their logarithmic equivalent using an inverting op-amp and a transistor in the feedback loop.

2.     Inversion of the Denominator:

To make the subtraction of the denominator easier we invert the polarity of the signal using an inverting op-amp with a gain of 1.

3.     Addition of the Inputs:

The outputs of the logarithmic amplifiers of the numerator and scaling factor along with the inverted output of the denominator are then fed to an analog adder which adds the logarithmic values effectively performing the division operation in the logarithmic domain.

4.     Antilogarithmic to get the output:

The result from the differential amplifier is then passed through an antilogarithmic amplifier to obtain the division.

Results