This block performs CVSD audio encoding. Its design and implementation is modeled after the CVSD encoder/decoder specifications defined in the Bluetooth standard.
More...
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| virtual short | min_step ()=0 |
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| virtual short | max_step ()=0 |
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| virtual double | step_decay ()=0 |
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| virtual double | accum_decay ()=0 |
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| virtual int | K ()=0 |
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| virtual int | J ()=0 |
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| virtual short | pos_accum_max ()=0 |
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| virtual short | neg_accum_max ()=0 |
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| unsigned | decimation () const |
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| void | set_decimation (unsigned decimation) |
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| void | forecast (int noutput_items, gr_vector_int &ninput_items_required) |
| | Estimate input requirements given output request. More...
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| int | general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items) |
| | compute output items from input items More...
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| int | fixed_rate_ninput_to_noutput (int ninput) |
| | Given ninput samples, return number of output samples that will be produced. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this. More...
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| int | fixed_rate_noutput_to_ninput (int noutput) |
| | Given noutput samples, return number of input samples required to produce noutput. N.B. this is only defined if fixed_rate returns true. Generally speaking, you don't need to override this. More...
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| virtual int | work (int noutput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)=0 |
| | just like gr::block::general_work, only this arranges to call consume_each for you More...
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| virtual | ~block () |
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| unsigned | history () const |
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| void | set_history (unsigned history) |
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| void | declare_sample_delay (int which, unsigned delay) |
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| void | declare_sample_delay (unsigned delay) |
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| unsigned | sample_delay (int which) const |
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| bool | fixed_rate () const |
| | Return true if this block has a fixed input to output rate. More...
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| virtual bool | start () |
| | Called to enable drivers, etc for i/o devices. More...
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| virtual bool | stop () |
| | Called to disable drivers, etc for i/o devices. More...
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| void | set_output_multiple (int multiple) |
| | Constrain the noutput_items argument passed to forecast and general_work. More...
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| int | output_multiple () const |
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| bool | output_multiple_set () const |
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| void | set_alignment (int multiple) |
| | Constrains buffers to work on a set item alignment (for SIMD) More...
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| int | alignment () const |
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| void | set_unaligned (int na) |
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| int | unaligned () const |
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| void | set_is_unaligned (bool u) |
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| bool | is_unaligned () const |
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| void | consume (int which_input, int how_many_items) |
| | Tell the scheduler how_many_items of input stream which_input were consumed. This function should be called at the end of work() or general_work(), after all processing is finished. More...
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| void | consume_each (int how_many_items) |
| | Tell the scheduler how_many_items were consumed on each input stream. More...
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| void | produce (int which_output, int how_many_items) |
| | Tell the scheduler how_many_items were produced on output stream which_output. More...
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| void | set_relative_rate (double relative_rate) |
| | Set the approximate output rate / input rate. More...
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| double | relative_rate () const |
| | return the approximate output rate / input rate More...
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| uint64_t | nitems_read (unsigned int which_input) |
| | Return the number of items read on input stream which_input. More...
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| uint64_t | nitems_written (unsigned int which_output) |
| | Return the number of items written on output stream which_output. More...
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| tag_propagation_policy_t | tag_propagation_policy () |
| | Asks for the policy used by the scheduler to moved tags downstream. More...
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| void | set_tag_propagation_policy (tag_propagation_policy_t p) |
| | Set the policy by the scheduler to determine how tags are moved downstream. More...
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| int | min_noutput_items () const |
| | Return the minimum number of output items this block can produce during a call to work. More...
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| void | set_min_noutput_items (int m) |
| | Set the minimum number of output items this block can produce during a call to work. More...
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| int | max_noutput_items () |
| | Return the maximum number of output items this block will handle during a call to work. More...
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| void | set_max_noutput_items (int m) |
| | Set the maximum number of output items this block will handle during a call to work. More...
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| void | unset_max_noutput_items () |
| | Clear the switch for using the max_noutput_items value of this block. More...
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| bool | is_set_max_noutput_items () |
| | Ask the block if the flag is or is not set to use the internal value of max_noutput_items during a call to work. More...
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| void | expand_minmax_buffer (int port) |
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| long | max_output_buffer (size_t i) |
| | Returns max buffer size on output port i. More...
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| void | set_max_output_buffer (long max_output_buffer) |
| | Request limit on max buffer size on all output ports. More...
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| void | set_max_output_buffer (int port, long max_output_buffer) |
| | Request limit on max buffer size on output port port. More...
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| long | min_output_buffer (size_t i) |
| | Returns min buffer size on output port i. More...
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| void | set_min_output_buffer (long min_output_buffer) |
| | Request limit on the mininum buffer size on all output ports. More...
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| void | set_min_output_buffer (int port, long min_output_buffer) |
| | Request limit on min buffer size on output port port. More...
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| float | pc_noutput_items () |
| | Gets instantaneous noutput_items performance counter. More...
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| float | pc_noutput_items_avg () |
| | Gets average noutput_items performance counter. More...
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| float | pc_noutput_items_var () |
| | Gets variance of noutput_items performance counter. More...
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| float | pc_nproduced () |
| | Gets instantaneous num items produced performance counter. More...
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| float | pc_nproduced_avg () |
| | Gets average num items produced performance counter. More...
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| float | pc_nproduced_var () |
| | Gets variance of num items produced performance counter. More...
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| float | pc_input_buffers_full (int which) |
| | Gets instantaneous fullness of which input buffer. More...
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| float | pc_input_buffers_full_avg (int which) |
| | Gets average fullness of which input buffer. More...
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| float | pc_input_buffers_full_var (int which) |
| | Gets variance of fullness of which input buffer. More...
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| std::vector< float > | pc_input_buffers_full () |
| | Gets instantaneous fullness of all input buffers. More...
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| std::vector< float > | pc_input_buffers_full_avg () |
| | Gets average fullness of all input buffers. More...
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| std::vector< float > | pc_input_buffers_full_var () |
| | Gets variance of fullness of all input buffers. More...
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| float | pc_output_buffers_full (int which) |
| | Gets instantaneous fullness of which input buffer. More...
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| float | pc_output_buffers_full_avg (int which) |
| | Gets average fullness of which input buffer. More...
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| float | pc_output_buffers_full_var (int which) |
| | Gets variance of fullness of which input buffer. More...
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| std::vector< float > | pc_output_buffers_full () |
| | Gets instantaneous fullness of all output buffers. More...
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| std::vector< float > | pc_output_buffers_full_avg () |
| | Gets average fullness of all output buffers. More...
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| std::vector< float > | pc_output_buffers_full_var () |
| | Gets variance of fullness of all output buffers. More...
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| float | pc_work_time () |
| | Gets instantaneous clock cycles spent in work. More...
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| float | pc_work_time_avg () |
| | Gets average clock cycles spent in work. More...
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| float | pc_work_time_var () |
| | Gets average clock cycles spent in work. More...
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| float | pc_work_time_total () |
| | Gets total clock cycles spent in work. More...
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| float | pc_throughput_avg () |
| | Gets average throughput. More...
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| void | reset_perf_counters () |
| | Resets the performance counters. More...
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| void | setup_pc_rpc () |
| | Sets up export of perf. counters to ControlPort. Only called by the scheduler. More...
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| bool | is_pc_rpc_set () |
| | Checks if this block is already exporting perf. counters to ControlPort. More...
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| void | no_pc_rpc () |
| | If the block calls this in its constructor, it's perf. counters will not be exported. More...
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| void | set_processor_affinity (const std::vector< int > &mask) |
| | Set the thread's affinity to processor core n. More...
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| void | unset_processor_affinity () |
| | Remove processor affinity to a specific core. More...
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| std::vector< int > | processor_affinity () |
| | Get the current processor affinity. More...
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| int | active_thread_priority () |
| | Get the current thread priority in use. More...
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| int | thread_priority () |
| | Get the current thread priority stored. More...
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| int | set_thread_priority (int priority) |
| | Set the current thread priority. More...
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| bool | update_rate () const |
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| void | system_handler (pmt::pmt_t msg) |
| | the system message handler More...
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| bool | finished () |
| | returns true when execution has completed due to a message connection More...
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| block_detail_sptr | detail () const |
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| void | set_detail (block_detail_sptr detail) |
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| void | notify_msg_neighbors () |
| | Tell msg neighbors we are finished. More...
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| void | clear_finished () |
| | Make sure we dont think we are finished. More...
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| pmt::pmt_t | message_subscribers (pmt::pmt_t port) |
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| virtual | ~basic_block () |
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| long | unique_id () const |
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| long | symbolic_id () const |
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| std::string | name () const |
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| std::string | symbol_name () const |
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| gr::io_signature::sptr | input_signature () const |
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| gr::io_signature::sptr | output_signature () const |
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| basic_block_sptr | to_basic_block () |
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| bool | alias_set () |
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| std::string | alias () |
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| pmt::pmt_t | alias_pmt () |
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| void | set_block_alias (std::string name) |
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| void | message_port_register_in (pmt::pmt_t port_id) |
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| void | message_port_register_out (pmt::pmt_t port_id) |
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| void | message_port_pub (pmt::pmt_t port_id, pmt::pmt_t msg) |
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| void | message_port_sub (pmt::pmt_t port_id, pmt::pmt_t target) |
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| void | message_port_unsub (pmt::pmt_t port_id, pmt::pmt_t target) |
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| virtual bool | message_port_is_hier (pmt::pmt_t port_id) |
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| virtual bool | message_port_is_hier_in (pmt::pmt_t port_id) |
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| virtual bool | message_port_is_hier_out (pmt::pmt_t port_id) |
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| pmt::pmt_t | message_ports_in () |
| | Get input message port names. More...
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| pmt::pmt_t | message_ports_out () |
| | Get output message port names. More...
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| void | _post (pmt::pmt_t which_port, pmt::pmt_t msg) |
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| bool | empty_p (pmt::pmt_t which_port) |
| | is the queue empty? More...
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| bool | empty_p () |
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| bool | empty_handled_p (pmt::pmt_t which_port) |
| | are all msg ports with handlers empty? More...
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| bool | empty_handled_p () |
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| size_t | nmsgs (pmt::pmt_t which_port) |
| | How many messages in the queue? More...
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| void | insert_tail (pmt::pmt_t which_port, pmt::pmt_t msg) |
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| pmt::pmt_t | delete_head_nowait (pmt::pmt_t which_port) |
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| pmt::pmt_t | delete_head_blocking (pmt::pmt_t which_port, unsigned int millisec=0) |
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| msg_queue_t::iterator | get_iterator (pmt::pmt_t which_port) |
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| void | erase_msg (pmt::pmt_t which_port, msg_queue_t::iterator it) |
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| virtual bool | has_msg_port (pmt::pmt_t which_port) |
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| const msg_queue_map_t & | get_msg_map (void) const |
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| virtual void | setup_rpc () |
| | Set up the RPC registered variables. More...
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| bool | is_rpc_set () |
| | Ask if this block has been registered to the RPC. More...
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| void | rpc_set () |
| | When the block is registered with the RPC, set this. More...
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| virtual bool | check_topology (int ninputs, int noutputs) |
| | Confirm that ninputs and noutputs is an acceptable combination. More...
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| template<typename T > |
| void | set_msg_handler (pmt::pmt_t which_port, T msg_handler) |
| | Set the callback that is fired when messages are available. More...
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| | msg_accepter () |
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| | ~msg_accepter () |
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| void | post (pmt::pmt_t which_port, pmt::pmt_t msg) |
| | send msg to msg_accepter on port which_port More...
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| | msg_accepter () |
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| enum | vcolor { WHITE,
GREY,
BLACK
} |
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| | sync_decimator (void) |
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| | sync_decimator (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature, unsigned decimation) |
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| | sync_block (void) |
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| | sync_block (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature) |
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| | block (void) |
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| | block (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature) |
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| void | set_fixed_rate (bool fixed_rate) |
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| void | add_item_tag (unsigned int which_output, uint64_t abs_offset, const pmt::pmt_t &key, const pmt::pmt_t &value, const pmt::pmt_t &srcid=pmt::PMT_F) |
| | Adds a new tag onto the given output buffer. More...
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| void | add_item_tag (unsigned int which_output, const tag_t &tag) |
| | Adds a new tag onto the given output buffer. More...
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| void | remove_item_tag (unsigned int which_input, uint64_t abs_offset, const pmt::pmt_t &key, const pmt::pmt_t &value, const pmt::pmt_t &srcid=pmt::PMT_F) |
| | DEPRECATED. Will be removed in 3.8. More...
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| void | remove_item_tag (unsigned int which_input, const tag_t &tag) |
| | DEPRECATED. Will be removed in 3.8. More...
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| void | get_tags_in_range (std::vector< tag_t > &v, unsigned int which_input, uint64_t abs_start, uint64_t abs_end) |
| | Given a [start,end), returns a vector of all tags in the range. More...
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| void | get_tags_in_range (std::vector< tag_t > &v, unsigned int which_input, uint64_t abs_start, uint64_t abs_end, const pmt::pmt_t &key) |
| | Given a [start,end), returns a vector of all tags in the range with a given key. More...
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| void | get_tags_in_window (std::vector< tag_t > &v, unsigned int which_input, uint64_t rel_start, uint64_t rel_end) |
| | Gets all tags within the relative window of the current call to work. More...
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| void | get_tags_in_window (std::vector< tag_t > &v, unsigned int which_input, uint64_t rel_start, uint64_t rel_end, const pmt::pmt_t &key) |
| | Operates like gr::block::get_tags_in_window with the ability to only return tags with the specified key. More...
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| void | enable_update_rate (bool en) |
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| | basic_block (void) |
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| | basic_block (const std::string &name, gr::io_signature::sptr input_signature, gr::io_signature::sptr output_signature) |
| | Protected constructor prevents instantiation by non-derived classes. More...
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| void | set_input_signature (gr::io_signature::sptr iosig) |
| | may only be called during constructor More...
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| void | set_output_signature (gr::io_signature::sptr iosig) |
| | may only be called during constructor More...
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| void | set_color (vcolor color) |
| | Allow the flowgraph to set for sorting and partitioning. More...
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| vcolor | color () const |
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| virtual bool | has_msg_handler (pmt::pmt_t which_port) |
| | Tests if there is a handler attached to port which_port. More...
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| virtual void | dispatch_msg (pmt::pmt_t which_port, pmt::pmt_t msg) |
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| std::vector< long > | d_max_output_buffer |
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| std::vector< long > | d_min_output_buffer |
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| gr::thread::mutex | d_setlock |
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| gr::logger_ptr | d_logger |
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| gr::logger_ptr | d_debug_logger |
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| std::string | d_name |
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| gr::io_signature::sptr | d_input_signature |
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| gr::io_signature::sptr | d_output_signature |
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| long | d_unique_id |
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| long | d_symbolic_id |
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| std::string | d_symbol_name |
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| std::string | d_symbol_alias |
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| vcolor | d_color |
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| bool | d_rpc_set |
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| msg_queue_map_t | msg_queue |
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| std::vector< boost::any > | d_rpc_vars |
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| pmt::pmt_t | d_message_subscribers |
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This block performs CVSD audio encoding. Its design and implementation is modeled after the CVSD encoder/decoder specifications defined in the Bluetooth standard.
CVSD is a method for encoding speech that seeks to reduce the bandwidth required for digital voice transmission. CVSD takes advantage of strong correlation between samples, quantizing the difference in amplitude between two consecutive samples. This difference requires fewer quantization levels as compared to other methods that quantize the actual amplitude level, reducing the bandwidth. CVSD employs a two level quantizer (one bit) and an adaptive algorithm that allows for continuous step size adjustment.
The coder can represent low amplitude signals with accuracy without sacrificing performance on large amplitude signals, a trade off that occurs in some non-adaptive modulations.
The CVSD encoder effectively provides 8-to-1 compression. More specifically, each incoming audio sample is compared to an internal reference value. If the input is greater or equal to the reference, the encoder outputs a "1" bit. If the input is less than the reference, the encoder outputs a "0" bit. The reference value is then updated accordingly based on the frequency of outputted "1" or "0" bits. By grouping 8 outputs bits together, the encoder essentially produce one output byte for every 8 input audio samples.
This encoder requires that input audio samples are 2-byte short signed integers. The result bandwidth conversion, therefore, is 16 input bytes of raw audio data to 1 output byte of encoded audio data.
The CVSD encoder module must be prefixed by an up-converter to over-sample the audio data prior to encoding. The Bluetooth standard specifically calls for a 1-to-8 interpolating up-converter. While this reduces the overall compression of the codec, this is required so that the encoder can accurately compute the slope between adjacent audio samples and correctly update its internal reference value.
References:
- Continuously Variable Slope Delta Modulation (CVSD) A Tutorial, Available: http://www.eetkorea.com/ARTICLES/2003AUG/A/2003AUG29_NTEK_RFD_AN02.PDF.
- Specification of The Bluetooth System Available: http://grouper.ieee.org/groups/802/15/Bluetooth/core_10_b.pdf.
- McGarrity, S., Bluetooth Full Duplex Voice and Data Transmission. 2002. Bluetooth Voice Simulink Model, Available: http://www.mathworks.com/company/newsletters/digest/nov01/bluetooth.html
Public Types inherited from gr::block
1.8.8