Transient Variable Area Downhole Inverse Models - Measurement While Drilling Signal Analysis, Optimization and Design - page 148

IF(T.GT.0.0) THEN
PI = 3.1415926
AMP = 0.5
F = 24.
PERIOD = 1./F
IF(T.GE.0.0.AND.T.LE.PERIOD) DELTAP =
1 +AMP*SIN(2.*PI*F*T)
IF(T.GE.PERIOD.AND.T.LE.2.*PERIOD) DELTAP =
1 -AMP*SIN(2.*PI*F*T)
IF(T.GE.2.*PERIOD) DELTAP = 0.
ENDIF
ENDIF
Figure 5.1c . Phase-shift-keying, 24 Hz carrier wave.
5.1.5 Run 3. Phase-shift-keying, 96 Hz carrier wave.
In this higher frequency 96 Hz run, the red curve is very different and
highly distorted from the green curve. The recovered black curve is very good.
C CASE 3. Standard phase shift keying
IF(NCASE.EQ.3) THEN
C F is frequency in Hz, AMP is delta-p amplitude in lbf/ft^2 (PSF),
C sampling time DT in seconds.
C 2*PI*F cycles in 2*PI secs, or F cycles per sec, F is Hz.
C One cycle requires time PERIOD = 1/F.
IF(T.LE.0.0) DELTAP = 0.
IF(T.GT.0.0) THEN
PI = 3.1415926
AMP = 0.5
F = 96.
PERIOD = 1./F
IF(T.GE.0.0.AND.T.LE.PERIOD) DELTAP =
1 +AMP*SIN(2.*PI*F*T)
IF(T.GE.PERIOD.AND.T.LE.2.*PERIOD) DELTAP =
1 -AMP*SIN(2.*PI*F*T)
IF(T.GE.2.*PERIOD) DELTAP = 0.
ENDIF
ENDIF