ted_init

Creation of a Timing Error Detector (TED)

Séquence d'appel

ted = ted_init();                // Default is Gardner detector
ted = ted_init('gardner'[,opt]); // Gardner
ted = ted_init('mm');            // Mueller and Muller detector
ted = ted_init('el');            // Early-late detector

Paramètres

opt:

optionnal option for Gardner detector: 'b' for basic Gardner, 'u' for upgraded Gardner (insensible to DC offset). If not specified, the ugraded version is selected.

ted:

the timing error detector object

Description

A timing error detector is an algorithm that can detect the current clock offset between the received signal and the local sampling clock. The timing error estimation is usually based on the detection of transitions in the received signal. Different estimators are included in the library:

  • Gardner detector:

    With 'b' option (basic), compute

    With 'u' option (upgraded), compute

  • Mueller and Muller detector:

    Compute with = received signal, and = estimated signal (here sign(r)).

    Restrictions :

    • AGC et DC offset correction are necessarily done before.
    • Needs only 1 sample / symbol.

  • Early-late gate detector, with delay = 1/2 symbol.

    Compute:

Exemple

ted = ted_init('mm');
plot_scurve(ted);


Voir aussi