Package builder.resid.residfp
Klasse ExternalFilter
java.lang.Object
builder.resid.residfp.ExternalFilter
The audio output stage in a Commodore 64 consists of two STC networks, a
low-pass filter with 3-dB frequency 16kHz followed by a high-pass filter with
3-dB frequency 16Hz (the latter provided an audio equipment input impedance
of 1kOhm).
The STC networks are connected with a BJT supposedly meant to act as a unity gain buffer, which is not really how it works. A more elaborate model would include the BJT, however DC circuit analysis yields BJT base-emitter and emitter-base impedances sufficiently low to produce additional low-pass and high-pass 3dB-frequencies in the order of hundreds of kHz. This calls for a sampling frequency of several MHz, which is far too high for practical use.
- Autor:
- Ken Händel
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Feldübersicht
FelderModifizierer und TypFeldBeschreibungprivate static final doubleprivate floathighpassprivate floatlowpassprivate floatCutoff frequencies.private floatCutoff frequencies. -
Konstruktorübersicht
Konstruktoren -
Methodenübersicht
Modifizierer und TypMethodeBeschreibungprotected floatclock(float Vi) SID clocking - 1 cycle.protected voidreset()SID reset.protected voidsetClockFrequency(double frequency) Setup of the external filter sampling parameters.protected void
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Felddetails
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LOWPASS_FREQUENCY
private static final double LOWPASS_FREQUENCY- Siehe auch:
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Vlp
private float Vlplowpass -
Vhp
private float Vhphighpass -
w0lp
private float w0lpCutoff frequencies. -
w0hp
private float w0hpCutoff frequencies.
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Konstruktordetails
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ExternalFilter
protected ExternalFilter()Constructor.
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Methodendetails
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clock
protected float clock(float Vi) SID clocking - 1 cycle.- Parameter:
Vi-
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zeroDenormals
protected void zeroDenormals() -
setClockFrequency
protected void setClockFrequency(double frequency) Setup of the external filter sampling parameters.- Parameter:
frequency- clock frequency
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reset
protected void reset()SID reset.
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