# Analog Devices Wiki

This version (30 Jun 2017 10:27) was approved by Venkatesan Krishnamoorthy.The Previously approved version (22 Jun 2012 14:39) is available. # Signal Subtract

There are two kinds of subtraction supported.

1. Subtraction (Real Signals)
2. Subtraction (Complex Signals)

## Subtraction (Real Signals)

The Subtract Block performs a subtraction operation on the input pins and outputs the difference result. (Minuend - Subtrahend = Difference)| |

### Input Pins

NameFormat [int/dec] - [control/audio]Function Description
Input_Pin 0any - anyMinuend term
Input_Pin 1any - anySubtrahend term

### Output Pins

NameFormat [int/dec] - [control/audio]Function Description
Input_Pin 0any - anyDifference term

### Algorithm Description

A standard subtraction operation is performed. When the algorithm is grown new input pins appear. These input pins represent more subtrahend terms so that the resulting output formula is:
Output_Pin 0 = Input_Pin 0 - (Input_Pin1 + Input_Pin2 + Input_Pin3 + … Input_PinN)

### Example

The subtraction block can be used along with other arithmetic operators to realize many typical DSP functions. It is a basic building block that allows difference operations to be performed.

The subtraction block can also be useful when debugging a schematic project. In the following example subtraction is used to compare the output of the Crossover Filter and two separate General 2nd Order filters set-up to do a cross-over functionality. By subtracting the two “low” outputs and the two “high” outputs, you can verify that both filters are the same if the resulting output in the Readback window is 0. ### Algorithm Details

 Toolbox Path Basic DSP - Arithmetic Operations - Signal Subtract Cores Supported ADAU144x ADAU176x ADAU178x ADAU170x AD1940 “Grow Algorithm” Supported yes - see Algorithm Growth Information “Add Algorithm” Supported no Subroutine/Loop Based no Program RAM 3* Data RAM 1 Parameter RAM 0

## Subtraction (Complex Signals)

This algorithm subtracts the complex signals. (All real parts are subtracted to the first signal's real part and all imaginary parts are subtracted to first signals imaginary part)This is a block based module. ### Input Pins

NameFormat [int/dec] - [control/audio]Function Description
Pin 0: Operand 1 complex Input complex signal 1
Pin 1: Operand 2 complex Input Complex signal 2

### Output Pins

NameFormat [int/dec] - [control/audio]Function Description
Pin 0: Output Signal Complex Complex output signal

### Grow Algorithm

input pins can be grown up to 8 channels.

### Supported DSPs  