gr_costas_loop_cc Class Reference
[Signal Processing Blocks]
#include <gr_costas_loop_cc.h>
Detailed Description
Carrier tracking PLL for QPSK
input: complex; output: complex
The Costas loop can have two output streams: stream 1 is the baseband I and Q; stream 2 is the normalized frequency of the loop.
order must be 2 or 4.
Public Member Functions | |
| int | work (int noutput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items) |
| just like gr_block::general_work, only this arranges to call consume_each for you | |
Friends | |
| gr_costas_loop_cc_sptr | gr_make_costas_loop_cc (float alpha, float beta, float max_freq, float min_freq, int order) throw (std::invalid_argument) |
| A Costas loop carrier recovery module. | |
Member Function Documentation
| int gr_costas_loop_cc::work | ( | int | noutput_items, | |
| gr_vector_const_void_star & | input_items, | |||
| gr_vector_void_star & | output_items | |||
| ) | [virtual] |
just like gr_block::general_work, only this arranges to call consume_each for you
The user must override work to define the signal processing code
Implements gr_sync_block.
References M_TWOPI.
Friends And Related Function Documentation
| gr_costas_loop_cc_sptr gr_make_costas_loop_cc | ( | float | alpha, | |
| float | beta, | |||
| float | max_freq, | |||
| float | min_freq, | |||
| int | order | |||
| ) | throw (std::invalid_argument) [friend] |
A Costas loop carrier recovery module.
The Costas loop locks to the center frequency of a signal and downconverts it to baseband. The second (order=2) order loop is used for BPSK where the real part of the output signal is the baseband BPSK signal and the imaginary part is the error signal. When order=4, it can be used for quadrature modulations where both I and Q (real and imaginary) are outputted.
More details can be found online:
J. Feigin, "Practical Costas loop design: Designing a simple and inexpensive BPSK Costas loop carrier recovery circuit," RF signal processing, pp. 20-36, 2002.
http://rfdesign.com/images/archive/0102Feigin20.pdf
- Parameters:
-
alpha the loop gain used for phase adjustment beta the loop gain for frequency adjustments max_freq the maximum frequency deviation (normalized frequency) the loop can handle min_freq the minimum frequency deviation (normalized frequency) the loop can handle order the loop order, either 2 or 4
The documentation for this class was generated from the following files:
