RedDifferentialManchesterCode | SuperCollider 3.13.0 Help

Description

Also known as biphase mark code (BMC). See http://en.wikipedia.org/wiki/Differential_Manchester_encoding

NOTE: There are two classes... one with positive edge clock (RedDifferentialManchesterCode) and one with negative edge clock (RedDifferentialManchesterCodeNegative).

Class Methods

.new

Creates a new encoder.

Arguments:

numBits	The maximum number of bits in the data to be encoded. The default 8 can deal with values between 0 and 255.
initPhase	Initial phase.

Instance Methods

.reset

To reset the phase to the initial value.

.encode

The lowest level method for encoding. Give and return arrays with raw 0/1 bits.

Arguments:

bits	An array of raw bits (zeros and ones) representing the n-bit value to be encoded. The length of this array should match numBits.

Returns:

An array of raw bits (zeros and ones) with encoded clock and data bits.

NOTE: The array returned will be double in length of the argument array (and also 2*numBits in length).

.encodeValue

A method for encoding single numbers. Converts the number to bits and then calls -encode.

Arguments:

value

Some number to be encoded. Make sure to not go above the current set numBits capacity (0-255 by default).

Returns:

Same as -encode above

.encodeArray

A method for encoding arrays of numbers.

Arguments:

array

Some array of numbers to be encoded.

Returns:

Same as -encode above

.numBits

Get or set the number of bits dynamically.

.phase

Get or set the phase dynamically (either 0 or 1).

//bigger number require more number of bits
RedDifferentialManchesterCode(11, 0).encodeValue(2r10011010010) //compare table in wikipedia article
RedDifferentialManchesterCodeNegative(11).encodeValue(2r10100111001)

a= RedDifferentialManchesterCode();
a.encode([0, 1, 1, 1, 0, 0, 1, 0])
a.encodeValue(114) //same but different
a.encodeArray([114, 114, 5]) //use this method for longer arrays

//if used as an audio signal it is often preferred to normalize the values -1 to 1.
//here is a simple way to do that normalization...
RedDifferentialManchesterCode(11).encode([1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0])*2-1

//--sound examples

//the example just sequence differential manchester encoded bytes.
(
SynthDef(\redBitsPlayer, {|out= 0, amp= 1, rate= 1000|
    var numBits= 8*2;  //double because of manchester encoding
    var data= Control.names([\data]).ir(Array.fill(numBits, 0));
    var src= Duty.ar(1/rate, 0, Dseq(data*2-1++0), 2);  //zero padded because doneAction2 is not stopping sample accurate
    OffsetOut.ar(out, src*amp!2);
}).add;
)

//test counter
(
t= 2400;  //datarate
Routine.run({
    var encoder= RedDifferentialManchesterCode(8);
    inf.do{|i|
        var byte= (i%256).asInteger;
        var data= encoder.encodeValue(byte);
        s.bind{
            Synth(\redBitsPlayer, [\out, 0, \data, data, \amp, 0.3, \rate, t]);
            ("playing:"+byte+data).postln;
        };
        (1/t*16).wait;
    };
});
)

//this example renders the 0-255 counter data in advance, normalize it and load it into a buffer
//stutter(8) means eight samples per data bit
b= Buffer.sendCollection(s, RedDifferentialManchesterCode().encodeArray((0..255)).stutter(8)*2-1)
b.play
b.free

//it is also possible to skip this class and do differential manchester code directly in the synthdef...
(
SynthDef(\redDifferentialManchesterEncode, {|out= 0, amp= 1, rate= 1000|
    var numBits= 8;
    var buf= LocalBuf(1).clear;
    var env= EnvGen.ar(Env(#[1, 1, 0], [16/rate, 0]), doneAction:2);
    var data= Control.names([\data]).ir(Array.fill(numBits, 0));
    var src= Duty.ar(1/rate, 0, Dswitch1([
        1-Dbufrd(buf),
        Dbufwr(1-Dseq(data).bitXor(Dbufrd(buf)), buf)
    ], Dseq(#[0, 1], numBits)));
    OffsetOut.ar(out, src*2-1*amp*env);
}).add;
)

Synth(\redDifferentialManchesterEncode, [\data, 154.asBinaryDigits, \amp, 0.2])
//record the result and compare with RedDifferentialManchesterCode().encodeValue(114)

helpfile source: HelpSource/Classes/RedDifferentialManchesterCode.schelp
link::redSys/Classes/RedDifferentialManchesterCode::

RedDifferentialManchesterCode
Extension

Description

Class Methods

.new

Arguments:

Instance Methods

.reset

.encode

Arguments:

Returns:

.encodeValue

Arguments:

Returns:

.encodeArray

Arguments:

Returns:

.numBits

.phase

Examples

RedDifferentialManchesterCodeExtension

Description

Class Methods

.new

Arguments:

Instance Methods

.reset

.encode

Arguments:

Returns:

.encodeValue

Arguments:

Returns:

.encodeArray

Arguments:

Returns:

.numBits

.phase

Examples

RedDifferentialManchesterCode
Extension