Livt.Signal

src/window/BlackmanWindowQ15.lvt

namespace Livt.Signal.Window

using Livt.Signal.Stream

/**
 * Symmetric three-term Blackman window with fixed Q1.15 coefficients.
 */
component BlackmanWindowQ15<SAMPLES: int>
{
	static assert SAMPLES == 8 || SAMPLES == 16 || SAMPLES == 32
		|| SAMPLES == 64 || SAMPLES == 128 || SAMPLES == 256
		|| SAMPLES == 512 || SAMPLES == 1024 || SAMPLES == 2048
		|| SAMPLES == 4096,
		"standard window length must be a supported power of two in 8..4096"

	// Published throughput, latency, capacity, and resource contract.
	public const INITIATION_INTERVAL: int = 1
	public const NOMINAL_LATENCY: int = 2
	public const CAPACITY: int = 2
	public const MULTIPLIER_COUNT: int = 1

	// Borrowed streams, fixed frame shape, and the owned standard-window datapath.
	inputStream: IQ15SampleStream
	outputStream: IQ15SampleStream
	shape: logic[SAMPLES]
	primitive: StandardWindowQ15PipelinePrimitive

	/**
	 * Binds borrowed endpoints to a symmetric Blackman window of fixed frame length.
	 */
	new(inputStream: IQ15SampleStream, outputStream: flip IQ15SampleStream)
	{
		this.inputStream = inputStream
		this.outputStream = outputStream
		primitive = new StandardWindowQ15PipelinePrimitive(shape, 2, false)
	}

	/**
	 * Connects the selected standard-window primitive to the stream endpoints.
	 */
	process Drive[]()
	{
		primitive.inputValid = inputStream.valid
		primitive.inputSample = inputStream.sample
		primitive.inputFirst = inputStream.first
		primitive.inputLast = inputStream.last
		primitive.outputReady = outputStream.ready
		inputStream.ready = primitive.inputReady
		outputStream.valid = primitive.outputValid
		outputStream.sample = primitive.outputSample
		outputStream.first = primitive.outputFirst
		outputStream.last = primitive.outputLast
	}
}