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zguig52 |
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---- Project: EurySPACE CCSDS RX/TX with wishbone interface
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---- Design Name: ccsds_tx_filter
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---- Version: 1.0.0
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---- Description:
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---- Transform symbols to samples, oversample signal and filter it with SRRC filter
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-------------------------------
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---- Author(s):
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---- Guillaume REMBERT
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-------------------------------
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---- Licence:
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---- MIT
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-------------------------------
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---- Changes list:
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---- 2016/11/06: initial release
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-------------------------------
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-- libraries used
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library ieee;
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use ieee.std_logic_1164.all;
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--=============================================================================
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-- Entity declaration for ccsds_tx / unitary tx filter inputs and outputs
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--=============================================================================
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entity ccsds_tx_filter is
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generic(
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constant CCSDS_TX_FILTER_BITS_PER_SYMBOL: integer; -- in bits
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constant CCSDS_TX_FILTER_OVERSAMPLING_RATIO: integer;
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constant CCSDS_TX_FILTER_OFFSET_IQ: boolean := true;
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constant CCSDS_TX_FILTER_MODULATION_TYPE: integer;
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constant CCSDS_TX_FILTER_SIG_QUANT_DEPTH: integer;
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constant CCSDS_TX_FILTER_TARGET_SNR: real := 40.0
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);
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port(
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-- inputs
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clk_i: in std_logic;
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rst_i: in std_logic;
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sym_i_i: in std_logic_vector(CCSDS_TX_FILTER_BITS_PER_SYMBOL-1 downto 0);
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sym_q_i: in std_logic_vector(CCSDS_TX_FILTER_BITS_PER_SYMBOL-1 downto 0);
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sym_val_i: in std_logic;
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-- outputs
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sam_i_o: out std_logic_vector(CCSDS_TX_FILTER_SIG_QUANT_DEPTH-1 downto 0);
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sam_q_o: out std_logic_vector(CCSDS_TX_FILTER_SIG_QUANT_DEPTH-1 downto 0);
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sam_val_o: out std_logic
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);
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end ccsds_tx_filter;
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--=============================================================================
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-- architecture declaration / internal components and connections
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--=============================================================================
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architecture structure of ccsds_tx_filter is
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component ccsds_tx_mapper_symbols_samples is
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generic(
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constant CCSDS_TX_MAPPER_TARGET_SNR: real;
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constant CCSDS_TX_MAPPER_BITS_PER_SYMBOL: integer;
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constant CCSDS_TX_MAPPER_QUANTIZATION_DEPTH: integer
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);
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port(
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clk_i: in std_logic;
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rst_i: in std_logic;
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sym_i: in std_logic_vector(CCSDS_TX_MAPPER_BITS_PER_SYMBOL-1 downto 0);
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sym_val_i: in std_logic;
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sam_val_o: out std_logic;
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sam_o: out std_logic_vector(CCSDS_TX_MAPPER_QUANTIZATION_DEPTH-1 downto 0)
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);
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end component;
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component ccsds_rxtx_oversampler is
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generic(
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CCSDS_RXTX_OVERSAMPLER_OVERSAMPLING_RATIO: integer;
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CCSDS_RXTX_OVERSAMPLER_SYMBOL_DEPHASING: boolean;
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CCSDS_RXTX_OVERSAMPLER_SIG_QUANT_DEPTH: integer
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);
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port(
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clk_i: in std_logic;
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sam_i: in std_logic_vector(CCSDS_RXTX_OVERSAMPLER_SIG_QUANT_DEPTH-1 downto 0);
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sam_val_i: in std_logic;
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rst_i: in std_logic;
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sam_o: out std_logic_vector(CCSDS_RXTX_OVERSAMPLER_SIG_QUANT_DEPTH-1 downto 0);
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sam_val_o: out std_logic
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);
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end component;
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component ccsds_rxtx_srrc is
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generic(
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CCSDS_RXTX_SRRC_OVERSAMPLING_RATIO: integer;
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CCSDS_RXTX_SRRC_SIG_QUANT_DEPTH: integer
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);
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port(
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clk_i: in std_logic;
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rst_i: in std_logic;
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sam_i: in std_logic_vector(CCSDS_RXTX_SRRC_SIG_QUANT_DEPTH-1 downto 0);
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sam_val_i: in std_logic;
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sam_o: out std_logic_vector(CCSDS_RXTX_SRRC_SIG_QUANT_DEPTH-1 downto 0);
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sam_val_o: out std_logic
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);
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end component;
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-- internal constants
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-- internal variable signals
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signal wire_sam_i: std_logic_vector(CCSDS_TX_FILTER_SIG_QUANT_DEPTH-1 downto 0);
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signal wire_sam_q: std_logic_vector(CCSDS_TX_FILTER_SIG_QUANT_DEPTH-1 downto 0);
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signal wire_sam_i_val: std_logic := '0';
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signal wire_sam_q_val: std_logic := '0';
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signal wire_sam_i_osr: std_logic_vector(CCSDS_TX_FILTER_SIG_QUANT_DEPTH-1 downto 0);
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signal wire_sam_q_osr: std_logic_vector(CCSDS_TX_FILTER_SIG_QUANT_DEPTH-1 downto 0);
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signal wire_sam_i_osr_val: std_logic;
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signal wire_sam_q_osr_val: std_logic;
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signal wire_sam_i_srrc_val: std_logic;
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signal wire_sam_q_srrc_val: std_logic;
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-- components instanciation and mapping
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begin
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tx_mapper_symbols_samples_i_0: ccsds_tx_mapper_symbols_samples
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generic map(
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CCSDS_TX_MAPPER_QUANTIZATION_DEPTH => CCSDS_TX_FILTER_SIG_QUANT_DEPTH,
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CCSDS_TX_MAPPER_TARGET_SNR => CCSDS_TX_FILTER_TARGET_SNR,
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CCSDS_TX_MAPPER_BITS_PER_SYMBOL => CCSDS_TX_FILTER_BITS_PER_SYMBOL
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)
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port map(
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clk_i => clk_i,
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sym_i => sym_i_i,
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sym_val_i => sym_val_i,
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rst_i => rst_i,
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sam_o => wire_sam_i,
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sam_val_o => wire_sam_i_val
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);
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tx_oversampler_i_0: ccsds_rxtx_oversampler
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generic map(
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CCSDS_RXTX_OVERSAMPLER_OVERSAMPLING_RATIO => CCSDS_TX_FILTER_OVERSAMPLING_RATIO,
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CCSDS_RXTX_OVERSAMPLER_SYMBOL_DEPHASING => CCSDS_TX_FILTER_OFFSET_IQ,
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CCSDS_RXTX_OVERSAMPLER_SIG_QUANT_DEPTH => CCSDS_TX_FILTER_SIG_QUANT_DEPTH
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)
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port map(
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clk_i => clk_i,
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sam_i => wire_sam_i,
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sam_val_i => wire_sam_i_val,
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rst_i => rst_i,
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sam_val_o => wire_sam_i_osr_val,
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sam_o => wire_sam_i_osr
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);
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tx_srrc_i_0: ccsds_rxtx_srrc
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generic map(
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CCSDS_RXTX_SRRC_OVERSAMPLING_RATIO => CCSDS_TX_FILTER_OVERSAMPLING_RATIO,
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CCSDS_RXTX_SRRC_SIG_QUANT_DEPTH => CCSDS_TX_FILTER_SIG_QUANT_DEPTH
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)
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port map(
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clk_i => clk_i,
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sam_i => wire_sam_i_osr,
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sam_val_i => wire_sam_i_osr_val,
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rst_i => rst_i,
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sam_o => sam_i_o,
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sam_val_o => wire_sam_i_srrc_val
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);
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-- BPSK
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BPSK_GENERATION: if (CCSDS_TX_FILTER_BITS_PER_SYMBOL = 1) and (CCSDS_TX_FILTER_MODULATION_TYPE = 2) generate
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sam_q_o <= (others => '0');
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wire_sam_q_srrc_val <= '1';
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end generate BPSK_GENERATION;
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-- nPSK
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NPSK_GENERATION: if (CCSDS_TX_FILTER_MODULATION_TYPE /= 2) or (CCSDS_TX_FILTER_BITS_PER_SYMBOL /= 1) generate
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tx_mapper_symbols_samples_q_0: ccsds_tx_mapper_symbols_samples
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generic map(
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CCSDS_TX_MAPPER_QUANTIZATION_DEPTH => CCSDS_TX_FILTER_SIG_QUANT_DEPTH,
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CCSDS_TX_MAPPER_TARGET_SNR => CCSDS_TX_FILTER_TARGET_SNR,
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CCSDS_TX_MAPPER_BITS_PER_SYMBOL => CCSDS_TX_FILTER_BITS_PER_SYMBOL
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)
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port map(
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clk_i => clk_i,
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sym_i => sym_q_i,
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sym_val_i => sym_val_i,
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rst_i => rst_i,
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sam_o => wire_sam_q,
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sam_val_o => wire_sam_q_val
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);
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tx_oversampler_q_0: ccsds_rxtx_oversampler
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generic map(
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CCSDS_RXTX_OVERSAMPLER_OVERSAMPLING_RATIO => CCSDS_TX_FILTER_OVERSAMPLING_RATIO,
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CCSDS_RXTX_OVERSAMPLER_SYMBOL_DEPHASING => false,
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CCSDS_RXTX_OVERSAMPLER_SIG_QUANT_DEPTH => CCSDS_TX_FILTER_SIG_QUANT_DEPTH
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)
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port map(
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clk_i => clk_i,
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sam_i => wire_sam_q,
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sam_val_i => wire_sam_q_val,
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rst_i => rst_i,
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sam_val_o => wire_sam_q_osr_val,
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sam_o => wire_sam_q_osr
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);
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tx_srrc_q_0: ccsds_rxtx_srrc
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generic map(
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CCSDS_RXTX_SRRC_OVERSAMPLING_RATIO => CCSDS_TX_FILTER_OVERSAMPLING_RATIO,
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CCSDS_RXTX_SRRC_SIG_QUANT_DEPTH => CCSDS_TX_FILTER_SIG_QUANT_DEPTH
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)
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port map(
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clk_i => clk_i,
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sam_i => wire_sam_q_osr,
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sam_val_i => wire_sam_q_osr_val,
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rst_i => rst_i,
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sam_o => sam_q_o,
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sam_val_o => wire_sam_q_srrc_val
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);
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end generate NPSK_GENERATION;
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--Valid samples indicator
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sam_val_o <= wire_sam_i_srrc_val and wire_sam_q_srrc_val;
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-- presynthesis checks
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CHKFILTERP0: if (CCSDS_TX_FILTER_BITS_PER_SYMBOL > 2*(CCSDS_TX_FILTER_SIG_QUANT_DEPTH-1)) generate
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process
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begin
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report "ERROR: BITS PER SYMBOL CANNOT BE HIGHER THAN 2*(CCSDS_TX_FILTER_SIG_QUANT_DEPTH-1)" severity failure;
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wait;
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end process;
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end generate CHKFILTERP0;
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end structure;
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