sah~
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sah~

Sample and hold a signal according to a trigger

Description

Use sah~ to capture ("sample") and continually output ("hold") the value of an input signal whenever another "control" signal rises above a specified threshold value. The sampled value is "held" until the control signal drops below and then rises above the threshold value once more, at which point the input is sampled again. Generally this allows one signal to be synchronized to the behavior of another.

Examples

Hold the signal value constant until the next trigger

Arguments

initial-trigger-value [number]

Optional

Initial trigger value

Attributes

Common Box Attributes

annotation [symbol]

Sets the text that will be displayed in the Clue window when the user moves the mouse over the object.

background [int] (default: 0)

Adds or removes the object from the patcher's background layer. background 1 adds the object to the background layer, background 0 removes it. Objects in the background layer are shown behind all objects in the default foreground layer.

color [4 floats]

Sets the color for the object box outline.

fontface [int]

Sets the type style used by the object. The options are:

plain
bold
italic
bold italic

Possible values:

0 = 'regular'
1 = 'bold'
2 = 'italic'
3 = 'bold italic'

fontname [symbol]

Sets the object's font.

fontsize [float]

Sets the object's font size (in points).

Possible values:

'8'
'9'
'10'
'11'
'12'
'13'
'14'
'16'
'18'
'20'
'24'
'30'
'36'
'48'
'64'
'72'

hidden [int] (default: 0)

Toggles whether an object is hidden when the patcher is locked.

hint [symbol]

Sets the text that will be displayed in as a pop-up hint when the user moves the mouse over the object in a locked patcher.

ignoreclick [int] (default: 0)

Toggles whether an object ignores mouse clicks in a locked patcher.

patching_rect [4 floats] (default: 0. 0. 100. 0.)

Sets the position and size of the object in the patcher window.

position [2 floats]

g/s(set)

Sets the object's x and y position in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its size unchanged.

presentation [int] (default: 0)

Sets whether an object belongs to the patcher's presentation.

presentation_rect [4 floats] (default: 0. 0. 0. 0.)

Sets the x and y position and width and height of the object in the patcher's presentation, leaving its patching position unchanged.

rect [4 floats]

g/s(set)

Sets the x and y position and width and height of the object in both patching and presentation modes (if the object belongs to its patcher's presentation).

size [2 floats]

g/s(set)

Sets the object's width and height in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its position unchanged.

textcolor [float]

Sets the color for the object's text in RGBA format.

textjustification [int]

Text Justification

Possible values:

0 = 'left'
1 = 'center'
2 = 'right'

varname [symbol]

Sets the patcher's scripting name, which can be used to address the object by name in pattr, scripting messages to thispatcher, and the js object.

Messages

float

Arguments

trigger-value [float]
Set trigger threshold

signal

In left inlet: A signal to be sampled. When the control signal (in the right inlet) goes from being at or below the current trigger value to being above the trigger value, the signal in the left inlet is sampled and its value is sent out as a constant signal value.

In right inlet: The control signal. In order to cause a change in the output of sah~, the control signal must go from being at or below the trigger value to above the trigger value. When this transition occurs, the signal in the left inlet is sampled and becomes the new output signal value.

Output

signal

When the control signal received in the right inlet goes from being at or below the trigger value to being above the trigger value, the output signal changes to the current value of the signal received in the left inlet. This signal value is sent out until the next time the trigger value is exceeded by the control signal.

See Also

Name Description
gate~ Route a signal to one of several outlets
phasor~ Generate sawtooth signals
thresh~ Detect signal above a set level
train~ Pulse train generator