File hbdecim_r2c_core.h¶

FileList > hbdecim > hbdecim_r2c_core.h

Real-to-complex halfband 2:1 decimator (Architecture D2). More...

#include "clib_common.h"
#include "dp_state.h"

Public Types¶

Type	Name
typedef struct hbdecim_r2c_state	hbdecim_r2c_state_t

Public Functions¶

Type	Name
hbdecim_r2c_state_t *	hbdecim_r2c_create (size_t num_taps, const float * h) Allocate a real-to-complex halfband decimator.
void	hbdecim_r2c_destroy (hbdecim_r2c_state_t * r)
size_t	hbdecim_r2c_execute (hbdecim_r2c_state_t * r, const float * in, size_t num_in, float _Complex * out, size_t max_out) Decimate real float32 input by 2, producing CF32.
size_t	hbdecim_r2c_get_num_taps (const hbdecim_r2c_state_t * r)
double	hbdecim_r2c_get_rate (const hbdecim_r2c_state_t * r)
void	hbdecim_r2c_get_state (const hbdecim_r2c_state_t * r, void * blob) Serialize `r's` mutable state into`blob` .
void	hbdecim_r2c_reset (hbdecim_r2c_state_t * r)
int	hbdecim_r2c_set_state (hbdecim_r2c_state_t * r, const void * blob) Restore mutable state from `blob` (same num_taps).
size_t	hbdecim_r2c_state_bytes (const hbdecim_r2c_state_t * r) Bytes hbdecim_r2c_get_state() writes for`r` (envelope+payload).

Macros¶

Type	Name
define	HBDECIM_R2C_STATE_MAGIC `[DP\_FOURCC](dp__state_8h.md#define-dp_fourcc) ('H', 'B', 'R', '2')`
define	HBDECIM_R2C_STATE_VERSION `1u`

Detailed Description¶

Lifted from dp_hbdecim_r2cf32_t (c/src/hbdecim.c). Accepts real float32 input and produces CF32 IQ at half the input rate, with an embedded fs/4 frequency shift (same effect as mixing with e^{jπn/2} before decimating, at zero extra multiplications).

The output at sample m is: y(m) = (FIR(even) + j·delay(odd)) · (-1)^m

where the sign pattern (-1)^m provides the fs/4 shift correction.

Lifecycle:

hbdecim_r2c_state_t *r = hbdecim_r2c_create(num_taps, h);
size_t n = hbdecim_r2c_execute(r, in, num_in, out, max_out);
hbdecim_r2c_destroy(r);

Public Types Documentation¶

typedef hbdecim_r2c_state_t¶

typedef struct hbdecim_r2c_state hbdecim_r2c_state_t;

Public Functions Documentation¶

function hbdecim_r2c_create¶

Allocate a real-to-complex halfband decimator.

hbdecim_r2c_state_t * hbdecim_r2c_create (
    size_t num_taps,
    const float * h
)

Parameters:

num_taps FIR branch length.
h FIR coefficients, float32, length num_taps.

Returns:

Non-NULL on success, NULL on invalid args or OOM.

function hbdecim_r2c_destroy¶

void hbdecim_r2c_destroy (
    hbdecim_r2c_state_t * r
)

Free all resources. NULL is a no-op.

function hbdecim_r2c_execute¶

Decimate real float32 input by 2, producing CF32.

size_t hbdecim_r2c_execute (
    hbdecim_r2c_state_t * r,
    const float * in,
    size_t num_in,
    float _Complex * out,
    size_t max_out
)

Parameters:

r Must be non-NULL.
in Real input samples.
num_in Number of input samples.
out CF32 output buffer.
max_out Capacity in samples.

Returns:

Number of output samples written.

function hbdecim_r2c_get_num_taps¶

size_t hbdecim_r2c_get_num_taps (
    const hbdecim_r2c_state_t * r
)

Returns the FIR branch length passed to hbdecim_r2c_create.

function hbdecim_r2c_get_rate¶

double hbdecim_r2c_get_rate (
    const hbdecim_r2c_state_t * r
)

Always returns 0.5.

function hbdecim_r2c_get_state¶

Serialize r's mutable state intoblob .

void hbdecim_r2c_get_state (
    const hbdecim_r2c_state_t * r,
    void * blob
)

function hbdecim_r2c_reset¶

void hbdecim_r2c_reset (
    hbdecim_r2c_state_t * r
)

Zero history and output parity without freeing.

function hbdecim_r2c_set_state¶

Restore mutable state from blob (same num_taps).

int hbdecim_r2c_set_state (
    hbdecim_r2c_state_t * r,
    const void * blob
)

Returns:

DP_OK, or DP_ERR_INVALID if the blob's envelope rejects.

function hbdecim_r2c_state_bytes¶

Bytes hbdecim_r2c_get_state() writes forr (envelope+payload).

size_t hbdecim_r2c_state_bytes (
    const hbdecim_r2c_state_t * r
)

Macro Definition Documentation¶

define HBDECIM_R2C_STATE_MAGIC¶

#define HBDECIM_R2C_STATE_MAGIC `DP_FOURCC ('H', 'B', 'R', '2')`

define HBDECIM_R2C_STATE_VERSION¶

#define HBDECIM_R2C_STATE_VERSION `1u`

The documentation for this class was generated from the following file native/inc/hbdecim/hbdecim_r2c_core.h