raddsp_axis_am_iq_modulator Datasheet

Use Cases

AXI-Stream datapath integration where module boundaries need explicit ready/valid behavior.
Reusable FPGA DSP pipelines that need fixed-point, timing-aware implementation.
Memory-mapped control/status integration with software-visible register maps.

Block Diagram

VHDL Include And Instantiation Template

File Header

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

library radhdl;
-- Direct entity instantiation below does not require importing the entity name.
use radhdl.dsp.all;
-- Narrower alternative: use radhdl.dsp_comms.all;

Component Declaration

component raddsp_axis_am_iq_modulator is
  generic (
    SAMPLE_WIDTH : positive := 16;
    FRAC_BITS : natural := 14;
    PHASE_WIDTH : positive := 32;
    REG_DATA_WIDTH : positive := 32;
    REG_ADDR_WIDTH : positive := 16;
    DEFAULT_PHASE_INC : natural := 16#01000000#;
    DEFAULT_INTERNAL_DDS : boolean := true;
    DEFAULT_ENABLE : boolean := true;
    VENDOR : string := "GENERIC";
    DEVICE_FAMILY : string := "GENERIC"
  );
  port (
    m_axis_tvalid : out std_logic;
    m_axis_tready : in std_logic;
    m_axis_tdata : out std_logic_vector((2 * SAMPLE_WIDTH) - 1 downto 0);
    m_axis_tlast : out std_logic;
    s_axis_tvalid : in std_logic;
    s_axis_tready : out std_logic;
    s_axis_tdata : in std_logic_vector(SAMPLE_WIDTH - 1 downto 0);
    s_axis_tlast : in std_logic;
    clk : in std_logic;
    rst : in std_logic;
    carrier_i_i : in std_logic_vector(SAMPLE_WIDTH - 1 downto 0);
    carrier_q_i : in std_logic_vector(SAMPLE_WIDTH - 1 downto 0);
    reg_wr_addr : in std_logic_vector(REG_ADDR_WIDTH - 1 downto 0);
    reg_rd_addr : in std_logic_vector(REG_ADDR_WIDTH - 1 downto 0);
    reg_wr_en : in std_logic;
    reg_rd_en : in std_logic;
    reg_data_in : in std_logic_vector(REG_DATA_WIDTH - 1 downto 0);
    reg_data_out : out std_logic_vector(REG_DATA_WIDTH - 1 downto 0);
    reg_wr_rdy : out std_logic;
    reg_rd_rdy : out std_logic;
    reg_wr_valid : out std_logic;
    reg_rd_valid : out std_logic;
    reg_error : out std_logic
  );
end component;

Direct Entity Instantiation

u_raddsp_axis_am_iq_modulator : entity radhdl.raddsp_axis_am_iq_modulator
  generic map (
    SAMPLE_WIDTH         => 16,
    FRAC_BITS            => 14,
    PHASE_WIDTH          => 32,
    REG_DATA_WIDTH       => 32,
    REG_ADDR_WIDTH       => 16,
    DEFAULT_PHASE_INC    => 16#01000000#,
    DEFAULT_INTERNAL_DDS => true,
    DEFAULT_ENABLE       => true,
    VENDOR               => "GENERIC",
    DEVICE_FAMILY        => "GENERIC"
  )
  port map (
    m_axis_tvalid => <m_axis_tvalid_signal>,
    m_axis_tready => <m_axis_tready_signal>,
    m_axis_tdata  => <m_axis_tdata_signal>,
    m_axis_tlast  => <m_axis_tlast_signal>,
    s_axis_tvalid => <s_axis_tvalid_signal>,
    s_axis_tready => <s_axis_tready_signal>,
    s_axis_tdata  => <s_axis_tdata_signal>,
    s_axis_tlast  => <s_axis_tlast_signal>,
    clk           => <clk_signal>,
    rst           => <rst_signal>,
    carrier_i_i   => <carrier_i_i_signal>,
    carrier_q_i   => <carrier_q_i_signal>,
    reg_wr_addr   => <reg_wr_addr_signal>,
    reg_rd_addr   => <reg_rd_addr_signal>,
    reg_wr_en     => <reg_wr_en_signal>,
    reg_rd_en     => <reg_rd_en_signal>,
    reg_data_in   => <reg_data_in_signal>,
    reg_data_out  => <reg_data_out_signal>,
    reg_wr_rdy    => <reg_wr_rdy_signal>,
    reg_rd_rdy    => <reg_rd_rdy_signal>,
    reg_wr_valid  => <reg_wr_valid_signal>,
    reg_rd_valid  => <reg_rd_valid_signal>,
    reg_error     => <reg_error_signal>
  );

Generics

Name	Type	Default	Description
SAMPLE_WIDTH	positive	16	Sample width for envelope, carrier, and I/Q output lanes.
FRAC_BITS	natural	14	Number of fractional bits used by carrier and envelope fixed-point values.
PHASE_WIDTH	positive	32	Internal DDS phase accumulator width. The register interface supports up to 32 bits.
REG_DATA_WIDTH	positive	32	Width of the RADIF register data path.
REG_ADDR_WIDTH	positive	16	Width of the RADIF byte address path.
DEFAULT_PHASE_INC	natural	16#01000000#	Reset value for carrier phase increment.
DEFAULT_INTERNAL_DDS	boolean	true	Reset value for internal DDS carrier selection.
DEFAULT_ENABLE	boolean	true	Reset value for stream processing enable.
VENDOR	string	"GENERIC"	Vendor selector retained for generated package consistency.
DEVICE_FAMILY	string	"GENERIC"	Device-family selector retained for generated package consistency.

Ports

Name	Direction	Type	Description
m_axis_tvalid	out	std_logic	Packed I/Q output valid.
m_axis_tready	in	std_logic	Packed I/Q output ready.
m_axis_tdata	out	std_logic_vector((2 * SAMPLE_WIDTH) - 1 downto 0)	Packed I/Q output, I in bits SAMPLE_WIDTH-1:0 and Q above it.
m_axis_tlast	out	std_logic	Output frame marker aligned with output sample.
s_axis_tvalid	in	std_logic	Envelope stream valid.
s_axis_tready	out	std_logic	Envelope stream ready.
s_axis_tdata	in	std_logic_vector(SAMPLE_WIDTH - 1 downto 0)	Signed fixed-point envelope sample.
s_axis_tlast	in	std_logic	Envelope stream frame marker.
clk	in	std_logic	Stream and register clock.
rst	in	std_logic	Active-high synchronous reset.
carrier_i_i	in	std_logic_vector(SAMPLE_WIDTH - 1 downto 0)	Signed fixed-point external carrier cosine sample.
carrier_q_i	in	std_logic_vector(SAMPLE_WIDTH - 1 downto 0)	Signed fixed-point external carrier sine sample.
reg_wr_addr	in	std_logic_vector(REG_ADDR_WIDTH - 1 downto 0)	Register write address.
reg_rd_addr	in	std_logic_vector(REG_ADDR_WIDTH - 1 downto 0)	Register read address.
reg_wr_en	in	std_logic	One-cycle register write request.
reg_rd_en	in	std_logic	One-cycle register read request.
reg_data_in	in	std_logic_vector(REG_DATA_WIDTH - 1 downto 0)	Register write data.
reg_data_out	out	std_logic_vector(REG_DATA_WIDTH - 1 downto 0)	Register read data.
reg_wr_rdy	out	std_logic	Register write ready.
reg_rd_rdy	out	std_logic	Register read ready.
reg_wr_valid	out	std_logic	Register write response valid.
reg_rd_valid	out	std_logic	Register read response valid.
reg_error	out	std_logic	Register transaction error.

Register Interfaces

Static register maps are rendered below for this module.

Interface	Directions	Signals	Representative ports
M_AXIS	in, out	4	m_axis_tvalid, m_axis_tready, m_axis_tdata, m_axis_tlast
S_AXIS	in, out	4	s_axis_tvalid, s_axis_tready, s_axis_tdata, s_axis_tlast
Register control/status	in, out	11	reg_wr_addr, reg_rd_addr, reg_wr_en, reg_rd_en, reg_data_in, reg_data_out, reg_wr_rdy, reg_rd_rdy, +3 more

Register Maps

raddsp_axis_am_iq_modulator

Source: dsp/hdl/raddsp/register_maps/raddsp_axis_am_iq_modulator.map.json

Controls AM envelope modulation, internal/external carrier selection, DDS tuning, and sample-count observation.

Register	Offset	Access	Reset	Description
control	0x00	rw	0x00000003	Controls stream processing and carrier source selection.
status	0x04	ro	0x00000002	Reports output-valid and input-ready status.
phase_inc	0x08	rw	0x01000000	Internal DDS phase increment applied after each accepted sample.
phase_offset	0x0C	rw	0x00000000	Static phase offset added to the accumulator before carrier lookup.
phase	0x10	ro	0x00000000	Current internal DDS phase accumulator value.
sample_count	0x14	rw	0x00000000	Counts accepted and emitted samples. Write bit 0 as one to clear the counter.

control

Offset 0x00 / Access rw / Reset 0x00000003

Controls stream processing and carrier source selection.

Control[15:0]

1514131211109876543210

RSVD [15:4]

PH RST

BYPASS

INT DDS

Control[31:16]

31302928272625242322212019181716

RSVD [31:16]

Name	Register bit(s)	Description
PH RST	Control[3]	Write-one strobe that clears the internal DDS phase accumulator.
BYPASS	Control[2]	Passes the envelope to the I lane and drives Q to zero without carrier multiplication.
INT DDS	Control[1]	Selects the internal DDS carrier. When clear, carrier_i_i and carrier_q_i provide the carrier samples.
EN	Control[0]	Enables stream processing. When clear, accepted input samples are dropped and no output samples are emitted.

status

Offset 0x04 / Access ro / Reset 0x00000002

Reports output-valid and input-ready status.

Status[15:0]

1514131211109876543210

RSVD [15:2]

READY

VALID

Status[31:16]

31302928272625242322212019181716

RSVD [31:16]

Name	Register bit(s)	Description
READY	Status[1]	Set when the block can accept an input envelope sample.
VALID	Status[0]	Set when an output I/Q sample is currently valid.

phase_inc

Offset 0x08 / Access rw / Reset 0x01000000

Internal DDS phase increment applied after each accepted sample.

PhaseInc[15:0]

1514131211109876543210

PH INC [15:0]

PhaseInc[31:16]

31302928272625242322212019181716

PH INC [31:16]

Name	Register bit(s)	Description
PH INC	PhaseInc[31:0]	Unsigned phase tuning word. Larger values increase carrier frequency; one full accumulator wrap equals one carrier cycle.

phase_offset

Offset 0x0C / Access rw / Reset 0x00000000

Static phase offset added to the accumulator before carrier lookup.

PhaseOffset[15:0]

1514131211109876543210

PH OFFS [15:0]

PhaseOffset[31:16]

31302928272625242322212019181716

PH OFFS [31:16]

Name	Register bit(s)	Description
PH OFFS	PhaseOffset[31:0]	Unsigned phase offset added to the DDS accumulator before sine/cosine lookup.

phase

Offset 0x10 / Access ro / Reset 0x00000000

Current internal DDS phase accumulator value.

Phase[15:0]

1514131211109876543210

PHASE [15:0]

Phase[31:16]

31302928272625242322212019181716

PHASE [31:16]

Name	Register bit(s)	Description
PHASE	Phase[31:0]	Current unsigned DDS phase accumulator value.

sample_count

Offset 0x14 / Access rw / Reset 0x00000000

Counts accepted and emitted samples. Write bit 0 as one to clear the counter.

SampleCount[15:0]

1514131211109876543210

COUNT [15:0]

SampleCount[31:16]

31302928272625242322212019181716

COUNT [31:16]

Name	Register bit(s)	Description
COUNT	SampleCount[31:0]	Current emitted-sample count. Writing bit 0 as one clears the counter.

Testbenches

tb_raddsp_axis_am_iq captured waveform

Source: dsp/hdl/testbenches/tb_raddsp_axis_am_iq.vhd

Verifies the register-controlled AM IQ modulator and demodulator with a 2048-sample amplitude envelope. The test programs both internal DDS mixers to the same carrier tuning word, streams a sinusoidal envelope through the modulator, demodulates it back to baseband, and exposes plot_* signals for datasheet analog plots.

Artifacts: status, vcd

Data Plots

AM IQ Input Envelope

Input amplitude envelope streamed into the AM IQ modulator over the full 2048-sample frame.

AM IQ Recovered Envelope

Envelope recovered by the demodulator after IQ modulation and DDS-based baseband rotation.

AM IQ Carrier Components

Modulated I and Q carrier components generated by the internal DDS-controlled mixer.

Captured GHDL Waveform

Source: dsp/hdl/testbenches/tb_raddsp_axis_am_iq.vhd

Horizontal Vertical

clk

rst

carrier_i[15:0]

carrier_q[15:0]

in_valid

in_ready

in_data[15:0]

in_last

iq_valid

iq_ready

iq_data[31:0]

iq_last

env_valid

env_ready

env_data[15:0]

env_last

reg_wr_addr[15:0]

reg_rd_addr[15:0]

reg_wr_en

reg_rd_en

reg_data_in[31:0]

mod_reg_data[31:0]

dem_reg_data[31:0]

mod_wr_valid

mod_rd_valid

dem_wr_valid

dem_rd_valid

mod_error

dem_error

sent_count

received_count

last_seen

plot_index[15:0]

plot_env_in[15:0]

plot_i[15:0]

plot_q[15:0]

plot_env_out[15:0]

carrier_i_i[15:0]

carrier_q_i[15:0]

reg_data_out[31:0]

reg_wr_rdy

reg_rd_rdy

reg_wr_valid

reg_rd_valid

reg_error

out_valid_r

out_data_r[31:0]

out_last_r

ready_i

enable_r

internal_dds_r

bypass_r

phase_r[31:0]

phase_inc_r[31:0]

phase_offset_r[31:0]

sample_count_r[31:0]

rd_data_r[31:0]

wr_valid_r

rd_valid_r

error_r

out_data_r[15:0]

S_AXIS

M_AXIS

M_AXIS interface signals

M_AXIS Interface Waveform

Source: dsp/hdl/testbenches/tb_raddsp_axis_am_iq.vhd

Horizontal Vertical

m_axis_tvalid

m_axis_tready

m_axis_tdata[31:0]

m_axis_tlast

m_axis_tdata[15:0]

S_AXIS interface signals

S_AXIS Interface Waveform

Source: dsp/hdl/testbenches/tb_raddsp_axis_am_iq.vhd

Horizontal Vertical

s_axis_tvalid

s_axis_tready

s_axis_tdata[15:0]

s_axis_tlast

s_axis_tdata[31:0]

Sources

dsp/hdl/raddsp/src/raddsp_axis_am_iq_modulator.vhd