# Quick Start

## Running dspsr

The `dspsr` command-line program processes baseband or filterbank data
into folded pulse profiles:

```bash
# Basic folding with 1024 phase bins
dspsr -b 1024 observation.dada

# Form a 256-channel convolving filterbank before folding
dspsr -F 256:D observation.dada
```

## Key concepts

**Data containers:**

**`dsp::TimeSeries`**
: Floating-point representation of the signal, organized by time,
  frequency, and polarization.

**`dsp::BitSeries`**
: N-bit digitized data before unpacking into a `TimeSeries`.

**Operations:**

All signal processing steps inherit from `dsp::Operation`:

- `dsp::Unpack` -- convert digitized data to floating point
- `dsp::Convolution` -- coherent dedispersion via convolution
- `dsp::Filterbank` -- filterbank channelization
- `dsp::Fold` -- fold data at the pulsar period
- `dsp::Detection` -- form Stokes parameters or detected power
- `dsp::PScrunch` / `dsp::TScrunch` / `dsp::FScrunch` --
  integrate over polarization, time, or frequency

**File loading:**

`dsp::File` and its subclasses handle format-specific I/O. The
`dsp::File::create` factory auto-detects the file format.