8min

Modulation

The Flipper supports several signal modulation settings.

In Read and Read RAW modes, the following Modulation settings are available for selection: AM270, AM650, FM238, FM476.

Each mode is a combination of signal modulation method and channel bandwidth.

In the AM270:

  • AM — means amplitude modulation
  • 270 — indicates a bandwidth of 270kHz.

What is modulation?

Modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a separate signal called the modulation signal that typically contains information to be transmitted. 

The flipper supports two types of modulation:

  • AM — the variable parameter is the amplitude of the signal.
  • FM — amplitude is unchanged, the frequency of the carrier signal changes.
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The flipper works with a demodulated signal that has already been converted from analog to digital by a TI CC1101 chip. Therefore it is important to select the correct modulation before starting the analysis in order to get the correct signal.

Bandwidth

This setting is used to set the limits of signal reception. It is necessary for quality signal reception. Each type of modulation has two levels of signal bandwidth/deviation. The frequency of the remote control is affected by the battery charge and the frequency of the quartz, which may not always have an exact level. Therefore, remotes can transmit a signal in which the frequency has a deviation from the stated frequency. Two different kinds of signal bandwidths/deviations can be used in the Flipper:

  • Narrow bandwidth allows you to record a signal with a better signal-to-noise ratio, which increases the range of the captured signal.
  • A wide band records a larger range in which many neighboring frequencies will be captured. Therefore, the device will catch more interference. But the Flipper will pick up the signal if the remote has a deviation from the declared frequency.





Updated 05 Apr 2022
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