Enter the frequency of the image, the frequency of the RF filter, and the quality factor into the calculator to determine the image frequency rejection ratio.

Image Frequency Rejection Ratio Formula

The following equation is used to calculate the Image Frequency Rejection Ratio.

IFRR = SQRT ( 1 + [(fi/frf)-(frf/fi)]^2*Q^2 )

  • Where IFRR is the image frequency rejection ratio
  • fi is the frequency of the image (hz)
  • frf is the frequency of the RF (hz)
  • Q is the quality factor

What is an Image Frequency Rejection Ratio ?


An image frequency rejection ratio is a metric that measured the performance of a radio receiver.

How to Calculate ?

Example Problem:

The following example outlines the steps and information needed to calculate Image Frequency Rejection Ratio.

First, determine the frequency of the image. In this example, the frequency is 600hz.

Next, determine the frequency of the RF. For this problem, the frequency is 1000hz.

Next, determine the quality factor. The quality factor for this problem is 1.5.

Finally, calculate the image response rejection ratio using the formula above:

IFRR = SQRT ( 1 + [(fi/frf)-(frf/fi)]^2*Q^2 )

IFRR = SQRT ( 1 + [(600/1000)-(1000/600)]^2*1.5^2 )

IFRR = 1886