# Hilbert Transform Instantaneous Trendline

Created by John Ehlers, the Hilbert Transform Instantaneous Trendline is a 5-period trendline of high/low price that that uses classic electrical radio-frequency signal processing algorithms reduce noise. Dominant Cycle Periods information is also provided. [Discuss]

```
// usage
IEnumerable<HtlResult> results =
quotes.GetHtTrendline();
```

## Historical quotes requirements

You must have at least `100`

periods of `quotes`

to cover the warmup periods.

`quotes`

is a collection of generic `TQuote`

historical price quotes. It should have a consistent frequency (day, hour, minute, etc). See the Guide for more information.

## Response

```
IEnumerable<HtlResult>
```

- This method returns a time series of all available indicator values for the
`quotes`

provided. - It always returns the same number of elements as there are in the historical quotes.
- It does not return a single incremental indicator value.
- The first
`6`

periods will have`null`

values for`SmoothPrice`

since there’s not enough data to calculate. - The first
`7`

periods will have`null`

values for`DcPeriods`

since there is not enough data to calculate; and are generally unreliable for the first ~25 periods.

Convergence warning: The first`100`

periods will have decreasing magnitude, convergence-related precision errors that can be as high as ~5% deviation in indicator values for earlier periods.

### HtlResult

`Date`

* DateTime* - Date from evaluated

`TQuote`

`DcPeriods`

* int* - Dominant cycle periods (smoothed)

`Trendline`

* double* - HT Trendline

`SmoothPrice`

* double* - Weighted moving average of

`(H+L)/2`

price### Utilities

See Utilities and helpers for more information.

## Chaining

This indicator may be generated from any chain-enabled indicator or method.

```
// example
var results = quotes
.Use(CandlePart.HLC3)
.GetHtTrendline(..);
```

Results can be further processed on `Trendline`

with additional chain-enabled indicators.

```
// example
var results = quotes
.GetHtTrendline(..)
.GetRsi(..);
```