TX Sample and Hold 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.

This stage appears in three different areas of the board, all near the right-hand edge. The areas are referred to below as the "top thirs, the middle third, and the bottom third of the board.

Board 'thirds' (go directly to build notes)

TX Sample and Hold Schematic

TX Sample and Holdschematic

(go directly to build notes)

TX Sample and Hold Bill of Materials

Stage Bill of Materials

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

CheckCountComponentMarkingCategory
❏11 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W
❏4100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W
❏610K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W
❏61K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W
❏333 1/4W 1%ora-ora-blk-gld-brn ora-ora-blk-gld-brn1/4W
❏13k3 1/4W 1% (3.3K)ora-ora-blk-brn-brn ora-ora-blk-brn-brn1/4W
❏247K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W
❏84K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W
❏1560 1/4W 1%grn-blu-blk-blk-brn grn-blu-blk-blk-brn1/4W
❏1560 1/4W 1%grn-blu-blk-blk-brn grn-blu-blk-blk-brn1/4W
❏81N41481N4148 1N4148Axial
❏11N41481N4148 1N4148Axial
❏110 nF (.01uF)103 103Ceramic
❏1100 nF104 104Ceramic
❏3100 nF104 104Ceramic
❏1100 nF104 104Ceramic
❏2NE5532 Dual OpAmpNE5532 NE5532DIP-8
❏2NE5532 Dual OpAmpNE5532 NE5532DIP-8
❏7100 uF/25Vdc Electrolytic
❏2misc hookup wireHookup
❏21 nF USM102J 102JMetalized polyfilm
❏210 nF USM103J 103JMetalized polyfilm
❏2100 nF USM104J 104JMetalized polyfilm
❏2180 pF USM181K 181KMetalized polyfilm
❏22.7 nF USM272J 272JMetalized polyfilm
❏4BC546 NPN Transistor TO-92
❏4BC556 PNP Transistor TO-92
❏15K (Y502)Y502 Y502Trimpot

TX Sample and Hold Summary Build Notes

TX Sample and Hold Detailed Build Notes

Top of the Board

TX Sample and Hold Top View

Install Top Third Active Components

Install Top Third Active Components photo
CheckDesignationComponentMarkingCategoryOrientationNotes
❏Q9-1BC556 PNP Transistor TO-92 
❏Q9-2BC556 PNP Transistor TO-92 
❏Q9-3BC546 NPN Transistor TO-92 
❏Q9-4BC546 NPN Transistor TO-92 
❏U9-1NE5532 Dual OpAmpNE5532 NE5532DIP-8 
Take ESD precautions

Install Top Third Passive Components

Install Top Third Passive Components photo
CheckDesignationComponentMarkingCategoryOrientationNotes
❏D9-41N41481N4148 1N4148Axial 
❏C9-16100 uF/25Vdc Electrolytic 
❏C9-17100 uF/25Vdc Electrolytic 
❏D9-11N41481N4148 1N4148Axial 
❏D9-21N41481N4148 1N4148Axial 
❏D9-31N41481N4148 1N4148Axial 
❏C9-10100 nF104 104Ceramic 
❏R9-4100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W 
❏R9-174K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
❏R9-184K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
❏R9-194K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
❏R9-204K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
❏R9-133 1/4W 1%ora-ora-blk-gld-brn ora-ora-blk-gld-brn1/4W 
❏R9-233 1/4W 1%ora-ora-blk-gld-brn ora-ora-blk-gld-brn1/4W 
❏R9-2510K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
❏R9-2610K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
❏R9-2710K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
❏R9-163k3 1/4W 1% (3.3K)ora-ora-blk-brn-brn ora-ora-blk-brn-brn1/4W 

Install Middle Third Active Components

Install Middle Third Active Components photo
CheckDesignationComponentMarkingCategoryOrientationNotes
❏Q9-5BC556 PNP Transistor TO-92 
❏Q9-6BC556 PNP Transistor TO-92 
❏Q9-7BC546 NPN Transistor TO-92 
❏Q9-8BC546 NPN Transistor TO-92 
❏U9-2NE5532 Dual OpAmpNE5532 NE5532DIP-8 
Take ESD precautions
❏R9-335K (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.

Install Middle Third Passive Components

In the component placement diagram on the website, there is a 100nF capacitor immediately to the left of the 5K trim pot. The diagram shows it as horizontally oriented but the latest version of the actual PCB shows it in a vertical orientation. There was a change in the PCB after the documentation herein was published. (TX to Al WA8LBZ for this tip)

Install Middle Third Passive Components photo
CheckDesignationComponentMarkingCategoryOrientationNotes
❏D9-101N41481N4148 1N4148Axial 
(reloc)
❏D9-51N41481N4148 1N4148Axial 
❏D9-61N41481N4148 1N4148Axial 
❏D9-71N41481N4148 1N4148Axial 
❏D9-81N41481N4148 1N4148Axial 
❏C9-710 nF (.01uF)103 103Ceramic 
❏C9-11100 nF104 104Ceramic 
❏C9-12100 nF104 104Ceramic 
❏C9-18100 uF/25Vdc Electrolytic 
❏C9-19100 uF/25Vdc Electrolytic 
❏R9-214K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
❏R9-224K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
❏R9-234K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
❏R9-244K7 1/4W 1% (4.7K)yel-vio-blk-brn-brn yel-vio-blk-brn-brn1/4W 
❏R9-333 1/4W 1%ora-ora-blk-gld-brn ora-ora-blk-gld-brn1/4W 
❏R9-5100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W 
❏R9-2810K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
❏R9-2910K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
❏R9-3010K 1/4W 1%brn-blk-blk-red-brn brn-blk-blk-red-brn1/4W 
❏R9-8560 1/4W 1%grn-blu-blk-blk-brn grn-blu-blk-blk-brn1/4W 
❏R9-91 k 1/4W 1%br-blk-blk-br-br br-blk-blk-br-br1/4W 

Install Bottom Third Active Components

Install Bottom Third Active Components photo
CheckDesignationComponentMarkingCategoryOrientationNotes
❏U9-3NE5532 Dual OpAmpNE5532 NE5532DIP-8 
Take ESD precautions
❏U9-4NE5532 Dual OpAmpNE5532 NE5532DIP-8 
Take ESD precautions
❏C9-31 nF USM102J 102JMetalized polyfilm 

Install Bottom Third Passive Components

Install Bottom Third Passive Components photo
CheckDesignationComponentMarkingCategoryOrientationNotes
❏C9-13100 nF104 104Ceramic 
❏C9-41 nF USM102J 102JMetalized polyfilm 
❏C9-52.7 nF USM272J 272JMetalized polyfilm 
❏C9-62.7 nF USM272J 272JMetalized polyfilm 
❏C9-810 nF USM103J 103JMetalized polyfilm 
❏C9-910 nF USM103J 103JMetalized polyfilm 
❏C9-23100 nF104 104Ceramic 
(reloc)
❏C9-14100 nF USM104J 104JMetalized polyfilm 
❏C9-15100 nF USM104J 104JMetalized polyfilm 
❏C9-1180 pF USM181K 181KMetalized polyfilm 
❏C9-2180 pF USM181K 181KMetalized polyfilm 
❏C9-20100 uF/25Vdc Electrolytic 
❏C9-21100 uF/25Vdc Electrolytic 
❏C9-22100 uF/25Vdc Electrolytic 
❏R9-101K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W 
❏R9-111K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W 
❏R9-121K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W 
❏R9-131K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W 
❏R9-141K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W 
❏R9-151K8 (1.8k) 1/4W 1%brn-gry-blk-brn-brn brn-gry-blk-brn-brn1/4W 
❏R9-6100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W 
❏R9-7100 1/4W 1%br-blk-blk-blk-br br-blk-blk-blk-br1/4W 
❏R9-34560 1/4W 1%grn-blu-blk-blk-brn grn-blu-blk-blk-brn1/4W 
❏R9-3147K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W 
❏R9-3247K 1/4W 1%yel-vio-blk-red-brn yel-vio-blk-red-brn1/4W 

Install Connecting Wires

Install Connecting wires

In this step you must install two connecting wires. The Genesis-Radio site's documentation refers to these as "W8" and "W9". The graphic in these notes refer to the wires by their end-points:

  • W8 is shown in the graphic as having end-points named "G"
  • W9 uses the letter "C" for its end-point names
    • \
W8 (Endpoints = "G")

Install connecting wire W8 between the two points marked "G"

These two points are shown, blown up, here:

W8 End Points (G-G)
W9 (Endpoints = "C")

Install connecting wire W9 between the two points marked "C"

These two points are shown, blown up, here:

W9 End Points (C-C)

CheckDesignationComponentMarkingCategoryOrientationNotes
❏W8misc hookup wireHookup 
❏W9misc hookup wireHookup 

TX Sample and Hold Testing

TX IQ Balance Resistance Adjustment

Test Setup

Power is OFF for this test

Make sure the G3020 is NOT connected to the sound card

This step adjusts the trimmer pot resistance in the TX IQ Balance Circuit. The intent is to have the resistance represented as "R12" equal the series resistance represented by the trimmer pot "R67" and the resistor "R60". The adjustment varys the trimmer until the series resistance is 3.3k ohms.

Test points are indicated as A and B in the graphic.

Measure the resistance while adjusting until it reads 3.3K ohms

TX IQ Balance Resistance Adjustment

Test Measurements

TestpointUnitsNominal ValueAuthor'sYours
A and B: measure resistanceohms3.3ktbd_______

Voltage Tests

Test Setup

Apply power to the board and measure the voltages at the test points

Voltage Tests

Test Measurements

TestpointUnitsNominal ValueAuthor'sYours
"A" (33 ohm resistor in top thirdVdc6.1tbd_______
"B" (33 ohm resistor in top thirdVdc6.1tbd_______
"C" (33 ohm resistor in middle thirdVdc6.1tbd_______
"D" (33 ohm resistor in middle thirdVdc6.1tbd_______