TX Sample Hold Modulator Introduction

General

This phase takes two signals (I and Q) from the PC Soundcard and produces four quadrature outputs to the bilateral mixing switches. The process is essentially the reverse of the RX side. Since the mixers are bilateral, the TX signals in quadrature go through the same process of sampling and holding, clocked by the Quadrature signals from the dividers.

TX Sample Hold Modulator Schematic

TX Sample Hold Modulatorschematic

TX Sample Hold Modulator Bill of Materials

Stage Bill of Materials

(resistor images and color codes courtesy of WIlfried, DL5SWB's R-Color Code program)

CheckCountComponentMarkingCategoryOrientationNotesCircuit
❏11 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W TX Sample Hold Modulator
❏610 k 1/4W 1%br-blk-blk-r-br br-blk-blk-r-br1/4W TX Sample Hold Modulator
❏4100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W TX Sample Hold Modulator
❏61K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W TX Sample Hold Modulator
❏333 1/4W 1%ora-ora-blk-gld-brn ora-ora-blk-gld-brn1/4W TX Sample Hold Modulator
❏13k3 1/4W 1% (3.3K)ora-ora-blk-brn-brn ora-ora-blk-brn-brn1/4W TX Sample Hold Modulator
❏247K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W TX Sample Hold Modulator
❏84K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W TX Sample Hold Modulator
❏2560 1/4W 1%grn-blu-blk-blk-brn grn-blu-blk-blk-brn1/4W TX Sample Hold Modulator
❏21 nF USM102J 102JCeramicshown in graphic as 102JTX Sample Hold Modulator
❏110 nF (.01uF)103 103Ceramic TX Sample Hold Modulator
❏210 nF USM103J 103JCeramicshown in graphic as 103JTX Sample Hold Modulator
❏5100 nF104 104ceramic TX Sample Hold Modulator
❏2100 nF USM104J 104JCeramicshown in graphic as 104JTX Sample Hold Modulator
❏2180 pF USM181K 181KCeramicshown in graphic as 181KTX Sample Hold Modulator
❏22.7 nF USM272J 272JCeramicshown in graphic as 272JTX Sample Hold Modulator
❏4NE5532 Dual OpAmp DIP-8 TX Sample Hold Modulator
❏7100 uF/25Vdc Electrolytic TX Sample Hold Modulator
❏2misc hookup wiremisc  TX Sample Hold Modulator
❏4BC546 NPN Transistor TO-92 TX Sample Hold Modulator
❏4BC556 PNP Transistor TO-92 TX Sample Hold Modulator
❏15K (Y502)Y502 Y502trimpot Needs to be initialized. Before installing this trimmer, adjust the resistance between the middle pin and either of the other pins to 2.5 K Ohm.TX Sample Hold Modulator

TX Sample Hold Modulator Summary Build Notes

TX Sample Hold Modulator Detailed Build Notes

Top of the Board

TX Sample Hold Modulator Top View

Uninstall CW Monitor Temporary Wire

Find the temporary wire placed during Phase 7 to enable CW Monitoring and uninstall it so as tp provide room for installing components in this phase.

This wire will be re-installed to the bottom of the board at the end of this phase.

Uninstall CW Monitor Temporary Wire photo

Install Bottom Right Components


USM capacitors chart:

1. 100nF [ 104J]
2. 100nF [ 104J]
3. 1 nF [ 102J]
4. 1 nF [ 102J]
5. 10 nF [ 103J]
6. 180 pF [181K]
7. 2.7 nF [272J]
8. 180 pF [181K]
9. 10 nF [ 103J]
10. 2.7 nF [272J]

CheckDesignationComponentMarkingCategoryOrientationNotes
❏E283180 pF USM181K 181KCeramic
shown in graphic as 181K
❏E300180 pF USM181K 181KCeramic
shown in graphic as 181K
❏E2881 nF USM102J 102JCeramic
shown in graphic as 102J
❏E2941 nF USM102J 102JCeramic
shown in graphic as 102J
❏E2932.7 nF USM272J 272JCeramic
shown in graphic as 272J
❏E2992.7 nF USM272J 272JCeramic
shown in graphic as 272J
❏E29110 nF USM103J 103JCeramic
shown in graphic as 103J
❏E29710 nF USM103J 103JCeramic
shown in graphic as 103J
❏E286100 nF104 104ceramic
❏E287100 nF104 104ceramic
❏E289100 nF USM104J 104JCeramic
shown in graphic as 104J
❏E290100 nF USM104J 104JCeramic
shown in graphic as 104J
❏E278100 uF/25Vdc Electrolytic
❏E279100 uF/25Vdc Electrolytic
❏E292100 uF/25Vdc Electrolytic
❏R45100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W
❏R78100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W
❏R5560 1/4W 1%grn-blu-blk-blk-brn grn-blu-blk-blk-brn1/4W
❏R221 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W
❏R821K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W
❏R831K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W
❏R841K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W
❏R851K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W
❏R861K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W
❏R871K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W
❏R7947K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W
❏R8147K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W
❏E188NE5532 Dual OpAmp DIP-8
Take ESD precautions
❏E285NE5532 Dual OpAmp DIP-8
Take ESD precautions

Install Upper Right Components

Install components as indicated in graphic

Install Upper Right Components photo
CheckDesignationComponentMarkingCategoryOrientationNotes
❏E254100 nF104 104ceramic
❏E27100 uF/25Vdc Electrolytic
❏E98100 uF/25Vdc Electrolytic
❏E2933 1/4W 1%ora-ora-blk-gld-brn ora-ora-blk-gld-brn1/4W
❏R13100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W
❏R673k3 1/4W 1% (3.3K)ora-ora-blk-brn-brn ora-ora-blk-brn-brn1/4W
❏R14K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
❏R164K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
❏R184K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
❏R24K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
❏R1110 k 1/4W 1%br-blk-blk-r-br br-blk-blk-r-br1/4W
❏R1710 k 1/4W 1%br-blk-blk-r-br br-blk-blk-r-br1/4W
❏R1910 k 1/4W 1%br-blk-blk-r-br br-blk-blk-r-br1/4W
❏E31BC546 NPN Transistor TO-92
❏E32BC556 PNP Transistor TO-92
❏E35BC546 NPN Transistor TO-92
❏E36BC556 PNP Transistor TO-92
❏E33NE5532 Dual OpAmp DIP-8
Take ESD precautions

Install Mid-Right Components

Install Mid-Right Components photo
CheckDesignationComponentMarkingCategoryOrientationNotes
❏E46NE5532 Dual OpAmp DIP-8
Take ESD precautions
❏E5610 nF (.01uF)103 103Ceramic
❏E338100 nF104 104ceramic
❏E57100 nF104 104ceramic
❏E24100 uF/25Vdc Electrolytic
❏E45100 uF/25Vdc Electrolytic
❏R433 1/4W 1%ora-ora-blk-gld-brn ora-ora-blk-gld-brn1/4W
❏R99933 1/4W 1%ora-ora-blk-gld-brn ora-ora-blk-gld-brn1/4W
❏R21100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W
❏R80560 1/4W 1%grn-blu-blk-blk-brn grn-blu-blk-blk-brn1/4W
❏R234K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
❏R254K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
❏R84K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
❏R94K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
❏R2010 k 1/4W 1%br-blk-blk-r-br br-blk-blk-r-br1/4W
❏R2410 k 1/4W 1%br-blk-blk-r-br br-blk-blk-r-br1/4W
❏R2610 k 1/4W 1%br-blk-blk-r-br br-blk-blk-r-br1/4W
❏E47BC546 NPN Transistor TO-92
❏E49BC546 NPN Transistor TO-92
❏E48BC556 PNP Transistor TO-92
❏E50BC556 PNP Transistor TO-92
❏E215K (Y502)Y502 Y502trimpot
Needs to be initialized. Before installing this trimmer, adjust the resistance between the middle pin and either of the other pins to 2.5 K Ohm.

Adjust Trimmer

(With Power OFF): Connect your ohmmeter between the following points : pin 2 of the NE5532 and the 1K resistor. Adjust the trimmer Y502 until the ohmmeter reads 3.3KO

Adjust Trimmer photo

Reinstall CW Monitor Wire (from Phase 5)

Reinstall W4, the wire placed during Phase 7 to enable CW Monitoring (permanently) on the underside of the board.

Reinstall CW Monitor Wire (from Phase 5) photo

Install Permanent Wires

Install permanent wires ("W8" and "W9") per the graphic. Click here for a higher-resolution view of the layout of these wires.


The end-points of the wires are annotated on the graphic:

  • W8: endpoints are marked "O"
  • W9: endpoints are marked "K"

Hint: use a short length of solder wire or other wire to act as a "marker" for each of the endpoint holes, permitting you to identify the hole for installation on the underside of the board.

Install Permanent Wires photo
CheckDesignationComponentMarkingCategoryOrientationNotes
❏W8misc hookup wiremisc 
❏W9misc hookup wiremisc 

TX Sample Hold Modulator Testing

No Tests at this Point

Test Setup

Procede to the next stage.