# Vpp Differential to dBm Calculator

This tool converts the differential peak-to-peak voltage to a power level in dBm and watt.

Enter

• Vpp for a single line
• Impedance Z in ohm (Ω)

## Formula

Vpp represents the difference between the min and max voltage of a single line. In the case of a differential pair the difference between two identical lines is given by VDiff = 2*Vpp

In this case, the dBm value can be calculated using the following relationship:

PdBm = 10*Log10((1/Z)*(VDiff/(2√2))2)

## Example Calculations

1 Volt peak-to-peak signal on one of the two lines of the differential pair, with 50 ohm results in 0.01 Watt or 10 dBm.

## What is a differential signal?

A differential signal is an electrical signal that consists of two signals that have opposite polarity but with the same amplitude. These two signals are transmitted on separate conductors and are designed to carry information based on the voltage difference between the two signals. ## How does a differential signal work?

When a differential signal is received by a receiver, it calculates the difference between the two signals. The result represents twice the original input voltage signal, while any noise or interference that is common to both signals is rejected. This differential signaling technique provides a high level of immunity to interference and allows for accurate signal transmission.

## What is the advantage of a differential signal over a single-ended signal?

A differential signal has several advantages over a single-ended signal. One of the main advantages is its ability to reject common-mode noise. Common-mode noise is present on both conductors of a signal transmission. Since a differential receiver only calculates the difference between the two signals, any noise that is common to both signals is automatically rejected.