PLL Carrier Tracking
Implements a Phase Locked Loop (PLL) which locks to the carrier of the input frequency and outputs the input signal mixed with that carrier.
This PLL locks onto a [possibly noisy] reference carrier on the input and outputs that signal, downconverted to DC.
- Important: The frequency parameters below are in radians per sample rather than Hz.
radians per sample = 2 * pi * freq / sample rate
- for example:
- input centered at 0 Hz.
- Sample rate = 48kHz.
- frequency variations to track +- 500Hz.
- Max freq = 0.0654
- Min freq = -0.0654
- If the input signal were to be at 10kHz, then the Max freq would be 1.374 and the Min freq would be 1.246
- This block seems to require an input signal of at least -30db in order to lock to the carrier.
- Loop bandwidth (R)
- The loop bandwidth determines the lock range and should be set in the range of pi/200 to 2pi/100 (0.0157 to 0.0628).
- Max freq
- Maximum frequency of the carrier in radians per sample. See Notes above.
- Min freq
- Minimum frequency of the carrier in radians per sample. See Notes above.
This flowgraph shows the use of a PLL Carrier Tracking block in an AM receiver.
- C++ files
- Header files
- Public header files
- Block definition