## Friday, December 22, 2017

### HP Prime and TI-84 Plus CE: Smith Chart Conversion (Post # 800)

HP Prime and TI-84 Plus CE: Smith Chart Conversion (Post # 800)

Happy Post 800!  Thank you readers and fans!  I wouldn’t be here without you!

Eddie

Introduction

The program SMITHCHART for the HP Prime and SMITH for the TI-84 Plus CE calculates one of two sets of conversions:

Return Loss (RL) to Standing Wave Ratio (SWR, in decibels):  RL to ρ (reflection coefficient) to σ (voltage standing ratio) to SWR

Standing Wave Ratio to Return Loss:  SWR to σ to ρ to RL

HP Prime Program SMITHCHART

EXPORT SMITHCHART()
BEGIN
// 2017-12-17 EWS
// Smith Chart Conversions
// HP 32S Engineering Applications
LOCAL k,x,RL,p,s,SWR;
INPUT({
{k,{"RL to SWR","SWR to RL"}},
x},"Smith Chart",
{"Starting at: ","Value: "});

IF k==1 THEN
// RL to SWR
RL:=x;
p:=ALOG(−RL/20);
s:=(1+p)/(1-p);
SWR:=20*LOG(s);
ELSE
// SWR to RL
SWR:=x;
s:=ALOG(SWR/20);
p:=(s-1)/(s+1);
RL:=20*LOG(1/p);
END;
// Results
PRINT();
PRINT("Results");
PRINT("Return Loss: "+RL);
PRINT(" ");
PRINT("Reflection Coefficient");
PRINT("ρ: "+p);
PRINT(" ");
PRINT("Voltage Standing Wave Ratio");
PRINT("σ: "+s);
PRINT(" ");
PRINT("SWR (dB): "+SWR);
END;

TI-84 Plus CE Program SMITH

"EWS 2017-12-17"
"HP 32S ENGINEERING"
Menu("SMITH CHART","RL TO SWR",1,"SWR TO RL",2)
Lbl 1
Input "RL: ",R
10^(­R/20)→P
(1+P)/(1-P)→I
20log(I)→S
Goto 3
Lbl 2
Input "SWR: ",S
10^(S/20)→I
(I-1)/(I+1)→P
20log(1/P)→R
Goto 3
Lbl 3
Disp "RETURN LOSS",R,"REFLECT COEFF.",P,"VOLT. STANDING WAVE",I,"SWR (DB)",S

Examples

SWR to RL:  Given 11.95 dB SWR

Results:
Return Loss:  4.48590571028
ρ: 0.59662948831
σ: 3.95822064836
SWR:  11.95

RL to SWR:  Given RL at 6.35 dB

Results:
Return Loss:  6.35
ρ: 0.481393254
σ: 2.85648666437
SWR:  9.11664401758

Source:
Hewlett-Pacakrd. Step by Step For Your HP Calculator:  Engineering Applications.  Ed. 1. Corvallis, OR January 1988

Eddie

This blog is property of Edward Shore, 2017

### Numworks: Allowing Repeated Calculations in Python

Numworks: Allowing Repeated Calculations in Python Introduction Say we want the user to repeat a calculation or a routine for as lo...