(42S) Smith Chart Conversions - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Software Libraries (/forum-10.html) +--- Forum: General Software Library (/forum-13.html) +--- Thread: (42S) Smith Chart Conversions (/thread-14038.html) (42S) Smith Chart Conversions - Eddie W. Shore - 11-23-2019 02:37 PM Introduction The program SMITH brings generates a custom menu that allows the user to convert between four factors: RL: return loss p: reflection coefficient s: voltage standing ratio SWR: standing wave ratio p = 10^-(RL/20) s = (1 + p)(1 - p) SWR = 20 * log s Programs here: HP 42S/DM42 Program: SMITH Code: ```00 { 111-Byte Prgm } 01▸LBL "SMITH" 02 "RL>p" 03 KEY 1 GTO 01 04 "p>s" 05 KEY 2 GTO 02 06 "s>SWR" 07 KEY 3 GTO 03 08 "SWR>s" 09 KEY 4 GTO 04 10 "s>p" 11 KEY 5 GTO 05 12 "p>RL" 13 KEY 6 GTO 06 14 MENU 15▸LBL 07 16 STOP 17 GTO 07 18▸LBL 01 19 +/- 20▸LBL 04 21 20 22 ÷ 23 10↑X 24 RTN 25▸LBL 02 26 STO 00 27 1 28 + 29 1 30 RCL- 00 31 ÷ 32 RTN 33▸LBL 05 34 STO 00 35 1 36 - 37 1 38 RCL+ 00 39 ÷ 40 RTN 41▸LBL 06 42 1/X 43▸LBL 03 44 LOG 45 20 46 × 47 RTN 48 .END.``` Example 1 Convert SWR of 12 to RL: [XEQ] (SMITH) 12 (SWR>s) (s>p) (p>RL) Result: 4.45901 Conversions Between Complex Reflection Coefficient and Impedance It is recommended that you set the calculator to Degree and Polar modes. To enter complex numbers in polar mode, Z→R: Convert from impedance to complex reflection coefficient Stack: Z, Z0 (characteristic impedance) Γ = (Z/Z0 - 1) / (Z/Z0 + 1) R→Z: Convert from complex reflection coefficient to impedance Stack: Z0, Γ Z = Z0 * (1 + Γ) / (1 - Γ) HP 42S/DM42 Programs: Z→R and R→Z Code: ```00 { 19-Byte Prgm } 01▸LBL "Z→R" 02 ÷ 03 ENTER 04 ENTER 05 1 06 - 07 X<>Y 08 1 09 + 10 ÷ 11 RTN 12 .END. 00 { 20-Byte Prgm } 01▸LBL "R→Z" 02 ENTER 03 ENTER 04 1 05 + 06 X<>Y 07 1 08 - 09 +/- 10 ÷ 11 × 12 RTN 13 .END.``` Example 2 In a system with the resistance of 66 Ω has the impedance of 10 ∠ 15°. What is the reflection coefficient? (Degree and Polar Mode) 10 [ENTER] 15 [(shift)] (COMPLEX) 66 [XEQ] ( Z→R ) Result: 0.40469 ∠ -163.92848 Example 3 What is the impedance of a system with a reflection coefficient of 0.86∠50° with a resistor of 125 Ω? (Degree and Polar Mode) 125 [ENTER] 0.86 [ENTER] 50 [(shift)] (COMPLEX) [XEQ] ( R→Z ) Result: 246.80096 ∠ 78.82055° Source: Step-by-Step Solutions For Your HP Calculator: Engineering Applications (HP-32S). Hewlett Packard. Edition 1. Corvallis, OR June 1988 Blog Link: http://edspi31415.blogspot.com/2019/11/hp-42s-dm42-smith-chart-conversions.html