Midian VPU-12A User Manual

VPU-12A

16-Code Voice Inversion Scrambler

Manual Revision: 2013-04-01

Covers Software Revisions:
VPU-12A: 3.0 and higher

1

SPECIFICATIONS

Operating Voltage +3.7-15 VDC
Operating Current 3.5 mA
Operating Temperature -30 - +60 C
Frequency Response – 2100 Hz 300-1700 Hz
Frequency Response – 3100 Hz 300-2500 Hz
Frequency Response – 4100 Hz 300-3600 Hz
Audio Output Impedance <10K
Input Level 150-1000 mV p-p
Input Impedance >60K
Frequency Error <0.25%
Device Gain or Loss Unity

Inversion Frequency Range 2100 – 4100 Hz
Number of Inversion Codes 16

GENERAL INFORMATION

Midian’s VPU-12A voice inversion scrambler provides an entry level of voice security for two-way radio
communications. The VPU-12A provides up to 16 different inversion frequencies that are selectable using 4-line
binary. These inversion frequencies are programmable using Midian’s KL-3. The VPU-12A is compatible with
Midian’s VPU-12, but adds the benefit of mode indications.

2

PRODUCT PROGRAMMING

The VPU-12A comes preprogrammed with default inversion frequencies (see Table 1 below). By configuring the
4-line binary outputs, the desired inversion frequency can be selected. Other default features are a Power-Up
State of Clear, a Mode Select of Momentary and a Mode Polarity of Active Low. If different parameters are
needed, the KL-4 programming interface and MPS programming software will be needed.

Table 1

Grounded Wires –

Frequency Select

(A, B, C, D)

Org/Wht, Gray, Gray/Wht, Grn/Wht 0000 1 2100
Org/Wht, Gray, Gray/Wht 0001 2 2341
Org/Wht, Gray, Grn/Wht 0010 3 2423
Org/Wht & Gray 0011 4 2587
Org/Wht, Gray/Wht, Grn/Wht 0100 5 2632
Org/Wht, Gray/Wht 0101 6 2728
Org/Wht, Grn/Wht 0110 7 2868
Org/Wht 0111 8 2976
Gray, Gray/Wht, Grn/Wht 1000 9 3023
Gray, Gray/Wht 1001 10 3107
Gray, Grn/Wht 1010 11 3333
Gray 1011 12 3388
Gray/Wht, Grn/Wht 1100 13 3500
Gray/Wht 1101 14 3729
Grn/Wht 1110 15 4096
None 1111 16 3276

The VPU-12A is programmed using the KL-4 programming interface and MPS programming software. Please
reference the KL-4 manual for setup of the programming hardware and software.

Set the parameters of the software to fit the application. If any clarifications on a feature are required, move the
mouse cursor over the feature name until the question mark appears and right click, a definition of the feature will
be shown.

After entering the parameters, save the file by going to File - Save As. Enter the file name in the File Name block
and click Save. Saving the file will allow for quick and easy reprogramming of units.

KL-4 Programming: Plug the board onto the KL-4 connector labeled as “P4”. Push and hold the power button
on the KL-4 and click “Program Unit” in the MPS software. The ACK LED on the KL-4 will faintly flash if
programmed successfully.

KL-4 Reading: Plug the board onto the KL-4 connector labeled as “P4”. Push and hold the power button on the
KL-4 and click “Read Unit” in the MPS software.

Binary Code # Inversion

Frequency

(Hz)

3

Switch Mode: Select whether the switch being used for mode selection is a momentary or latched switch.
Power Up State: Select the mode you wish the scrambler to go into upon power up.
Clr/Scr Polarity: If +/- is selected then the clear mode will be a positive polarity and scramble mode will be a

negative polarity. If -/+ is selected then the clear mode will be a negative polarity and scramble mode will be a
positive polarity.

Code 1-16: Set the desired inversion frequency for each code position. The table on the previous page shows
which code is selected based upon which 4-line binary inputs are selected. If only one code is being used,
program that code in Code 16 and do not connect any of the 4-line binary inputs.

4

HARDWARE INSTALLATION

Be certain to follow standard anti-static procedures when handling any of Midian’s products.

P1-4 – Black – Ground – Connect to the nearest ground point.
P1-2 – Red - +3.7 – 15 VDC – Connect to switched B+ in the radio.
P1-6 – Orange – RX Input – Connect after the CTCSS high-pass filter in radios using CTCSS or DCS. Failure to

do so will cause the CTCSS to be inverted from a low to a high frequency. Other signaling tones that might be
used on the system should be decoded before the scrambler input. The audio path should be broken with this
lead connected to the break point closest to the discriminator.

P1-13 – Violet – RX Output – Connect to the break point described in the RX Input on the side closest to the
speaker.

P1-9 – White – TX Input – Connect to the radio modulator circuit before the insertion point for CTCSS or other
tone signaling. The audio path is broken and this lead is connected to the break point closest to the microphone.

P1-1 – Green – TX Output – Connect to the break point described in TX Input on the side closest to the
modulator.

P1-7 – Yellow – PTT Input – Selection of the RX or TX path is provided via this lead. A ground from the PTT
switch will select TX & releasing the ground will select RX.

P1-3 – Brown – Mode Input/Program Out – Connect to a momentary or latched switch for selection of scramble
or clear modes. For program out, connect this lead to the yellow clip lead from the KL-3.

P1-5 – Blue – Program In – Connect this wire to the green clip lead from the KL-3.
P1-8 – Green/White – Frequency Select A – Frequency select A, B, C and D are used to determine the selected

inversion frequency (see Table 1 above).
P1-10 – Gray/White – Frequency Select B – Frequency select A, B, C and D are used to determine the selected

inversion frequency (see Table 1 above).
P1-11 – Gray – Frequency Select C or Mode LED – Frequency select A, B, C and D are used to determine the

selected inversion frequency (see Table 1 above).
When used for Mode LED install R-34 and remove D4. Connect this wire to the cathode of the LED and connect

the anode of the LED to V+. The Mode LED output provides an active low.
P1-12 – Orange/White – Frequency Select D or Audio Enable – Frequency select A, B, C and D are used to

determine the selected inversion frequency (see Table 1 above).
When used for Audio Enable install R-36 and remove D-3. Connect this wire to a point in the radio that when

grounded turns on the audio amplifier.
Mode LED: If the frequency select lines are being used for inversion frequency selection, the Mode LED hole can

have a wire added. Connect this wire to the cathode of the LED and connect the anode of the LED to V+. The
Mode LED output provides an active low.

Audio Enable: If the frequency select lines are being used for inversion frequency selection the Audio Enable
hole can have a wire added. Connect this wire to a point in the radio that when grounded turns on the audio
amplifier.

5

RADIO PROGRAMMING

The VPU-12A is a generic module that wires into most radios. Any radio specific programming, if available, would
be found on any Application Notes available for those radios. You may visit our website or call us for application
notes.

HARDWARE ALIGNMENT

The VPU-12A is a unity gain device. If for some reason more or less gain is needed adjust R-2, R-12, R-18 or R­19 as needed. For the TX Input, Midian recommends having 1 V p-p at Pin 1 of IC-5. Adjusting R-2 will adjust the
level at Pin 1 of IC-5.

For the RX Input, Midian recommends having 1 V p-p at Pin 7 of IC-5. Adjusting R-12 will adjust the level at Pin 7
of IC-5.

For the TX Output, Midian recommends matching the level of the radio that is present at the TX Input (P1-9).
For the RX Output, Midian recommends matching the level of the radio that is present at the RX Input (P1-6).

6

OPERATION

Mode Selection: The mode of the VPU-12A can be controlled by a momentary or latched switch.

Latched Switch: Programming the VPU-12A to latched with a Mode Polarity of +/- will cause the scrambler to

be in clear mode when high and scramble mode when taken to ground. A Mode Polarity of -/+ will cause the
scrambler to be in clear mode when taken to ground and scramble mode when high.

Momentary Switch: Programming the VPU-12A to momentary with a Mode Polarity of +/- will cause the

scrambler to toggle modes when taken to ground. A Mode Polarity of -/+ will cause the scrambler to toggle

modes when taken high.
Code Selection:
Single Code: If only a single inversion frequency is desired connect the frequency select lines to ground as

indicated in Table 1 above. Otherwise if no frequency select lines are grounded code 16 will be selected.
Multi-Code: The VPU-12A has a 4-line binary input that can be used to select from 16 different inversion

frequencies (see Table 1 above).

7

TECHNICAL NOTES

Pre-emphasis/De-emphasis: The scrambler should be installed before pre-emphasis and after de-emphasis.

If installed after pre-emphasis and before de-emphasis, the recovered audio may be noisier due to the
amplification of the noise.

If installed before pre-emphasis and before de-emphasis, recovered audi o will be de-emp hasized (bassy).
If installed after pre-emphasis and after de-emphasis, recovered au dio is pre-emphasized (tinny).

MIDIAN CONTACT INFORMATION

MIDIAN ELECTRONICS, INC.

2302 East 22

nd

Street

Tucson, Arizona 85713 USA

Toll-Free: 1-800-MIDIANS
Main: 520-884-7981
E-mail:

[e-mail]

Web: HUwww.midians.comU

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MIDIAN ELECTRONICS, INC.

DATE:

DESIGN:

DWN BY:

REV:

APPR

COPYRIGHT ©

REV

SHEET

PROJECT NUMBER

DOCUMENT NAME

SCHEMATIC

2013

VPU-12A

47K

R8

47K

R1

SD1

D1

3.3V

3.3V

RA2

1

RA3

2

TOCK1

3

MCRL

4

VSS5VSS

6

RB0

7

RB1

8

RB2

9

RB3

10

RB4

11

RB5

12

RB6

13

RB7

14

VDD15VDD

16

OSC2

17

OSC1

18

RA0

19

RA1

20

16LF818

IC1

TP3

560p

C11

100K

R21

100K

R2

560p

C29

.1u

C13

-

+

2

3

1

LMV324

IC5:1

-

+

6

5

7

LMV324

IC5:2

-

+

9

10

8

LMV324

IC5:3

-

+

13

12

14

LMV324

IC5:4

4

VCCVCC

11

GNDGND

LMV324

IC5:5

VAN

560p

C12

100K

R20

100K

R12

.1u

C14

VAN

A11A

11

X012X0

12

X113X1

13

X14X

14

4053

IC2:1

B10B

10

Y11Y1

1

Y02Y0

2

Y15Y

15

4053

IC2:2

C9C

9

Z4Z

4

Z05Z0

5

Z13Z1

3

E\6E\

6

VCC16VCC

16

VEE7VEE

7

GND8GND

8

4053

IC2:3

SD1

D2

BSS

Q2

560p

C3

18K

R13

12K

R14

.012u

C10

BSS

Q1

-

+

2

3

1

LMV358

IC3:1

-

+

6

5

7

LMV358

IC3:2

8

VCCVCC

4

GNDGND

LMV358

IC3:3

10K1%

R15

47K

R10

36K

R11

.001u

C9

10K1%

R16

.01u

C6

.01u

C4

100p

C22

SD1D3

SD1D4

SD1D6

SD1D5

BSS

Q3

BSS

Q4

47K

R33

330R

R37

3.3V TP1

MODE LED

*

R34

BSS

Q5

.1u

C28

220K

R35

*

R36

TP2

AUDIO EN

SHDN

7

V+

4

CLK

8

IN

2

OUT

5

COM

1OS6

V-

3

7427

IC4

.1u

C16

.1u

C15

VAN

.01u

C19

3.3V

.1u

C18

3.3V

47K

R23

3.3V

100K

R18

100K

R19

100K

R32

.01u

C25

4.7K

R30

220K

R31

.01u

C7

560p

C27

100K

R22

VAN

.1u

C1

VAN

560p

C26

100K

R17

.1u

C2

*

C30

5206

IN1

1

ENA

3

GND

2

RES

4

OUT

5

VR1

.1u

C8

.1u

C17

3.3V

3.3V3.3V

TX OUT[GRN]

P1:1

+3.7V to +15V[RED]

P1:2

CLR/SCR/PROG OUT[BRN]

P1:3

GND

P1:4

PROG IN[BLUE]

P1:5

RX IN[ORG]

P1:6

RX/TX[YEL]

P1:7

FS A[GRN/WHT]P1:8

TX IN[WHT]

P1:9

FS B[GRAY/WHT]P1:10

FS C/MODE LED[GRAY]P1:11

FS D/AUDIO EN[ORG/W]P1:12

RX OUT[VIO]

P1:13

.01u

C21

3.3V

10 MHz.

Y1

1K

R3

OSC1

OSC2

OSC1

OSC2

22p

C23

22p

C24

.01u

C20

VIN

VIN

FREQUENCY SELECT

**

***

** = TO USE MODE LED REMOVE D4 AND INSTALL R34

*** = TO USE AUDIO EN REMOVE D3 AND INSTALL R36

* = NOT INSTALLED

PIY101
PIY102

COR3

PIR301 PIR302

PIR801

COR8

COC13

COC14

PIC1401PIC1402

PIR802

PIR101

COR1

PIR102

COR2

PIR201

COR12

PIR1202

PIC302

COC3

PIC301

PIR202

PIR1201

COC11

PIC1101 PIC1102

COR21

PIR2101 PIR2102

PIIC502

PIIC503

COIC5:1

COC12

PIC1201PIC1202

COR20

PIR2001PIR2002

PIIC506

PIIC505

COIC5:2

COD2

PIQ20D

COQ2

PIQ20G

PIQ20S

PIIC501

PIIC507

PID201PID202

COD1

PID101PID102

PIP103

COP1:3

PIP105

COP1:5

PIC1301 PIC1302

PIP109

COP1:9

COP1:6

COP1:7

PIP106

PIP107

PIC2901

COC29

PIC2902

COY1

COTP3

PIIC2012

PIIC2013

COIC2:1

PIC2402

COC24

PIC2401
PIC2301

PIC2302

COIC1

PIIC101

PIIC103

PIIC107

PITP301

PIIC102
PIIC104

PIIC1017

PIIC1018

PIIC2011

PIIC2014

COC23

PIIC1015 PIIC1016

PIIC105 PIIC106

PIQ10G

PIC402

COC4

PIC401

COR13

PIC2101

COC21

PIC2102

PIIC1020

PIIC1019

PIIC1011

PIIC1012

PIIC1013

PIIC1014

PIIC108
PIIC1010
PIIC109

PIQ10D

COQ1

PIQ10S

PIR1301PIR1302

PIR1401 PIR1402

PIC1001
PIC1002

COR14

COC10

COD6

PID601 PID602

COD5

PID501 PID502

COD4

PID401 PID402

COD3

PID301 PID302

COR10

PIR1001 PIR1002

COR11

COC9

PIIC302

PIIC303

COIC3:1

PIC601

COC6

PIC602

PIP108

COP1:8

PIP1010

COP1:10

PIP1011

COP1:11

PIP1012

COP1:12

PIQ30G

PIR3302

COR33

PIQ40D

PIR3301

COQ4

PIQ40G

PIQ30D

PIQ40S

COQ3

PIQ30S

COR37

COTP1

PIR3701PIR3702

PITP101

PIR3401

COR34

PIR3402

PIR3501

COR35

PIR3502

PIQ50G

PIC2801

COC28

PIC2802

COTP2

PITP201

PIQ50D

PIR3602

COQ5

PIQ50S

PIR3601

COR36

PIR3102

PIR3201

COC7

PIR1801

COR31

PIR3101

PIC701
PIC702

PIIC509

PIIC5010

COC26

PIC2601PIC2602

COR17

PIR1701PIR1702

PIIC5013

PIIC5014

PIIC5012

COIC5:4

COC27

PIC2701 PIC2702

COR22

PIR2201 PIR2202

PIIC508

COIC5:3

COC30

PIC3001
PIC3002

COC2

PIC201 PIC202

PIC101 PIC102

COC1

PIP101

PIP1013

COP1:1

COP1:13

COIC2:3

PIIC2016

PIIC205

PIIC203

PIIC209

PIR2301

PIR2302

PIR3002

COR30

PIR3001

PIR3202

PIC2502

COC25

PIC2501

PIR1901 PIR1902

PIR1802

COR23

COR32

COR19

COR18

PIIC2010

PIIC201

PIR1101PIR1102

PIC901PIC902

PIIC301

COR15

PIR1601 PIR1602

PIIC306

PIR1501PIR1502

PIIC305

COR16

COIC3:2

PIIC307

PIIC202

COIC2:2

PIIC2015

PIC2202
PIC2201

PIC1602

COC16

PIC1601

PIIC402

COC22

PIC1502

COC15

PIC1501

PIC2002

COC20

PIC2001

PIIC407PIIC408

PIIC401

PIIC406

PIC1902

COC19

PIC1901

PIIC404

COIC4

PIIC405

PIIC403

PIC1801

COC18

PIC1802

PIIC204
PIIC208
PIIC207
PIIC206

COP1:4

PIP102

PIP104

PIC802

COC8

PIC801

PIVR101

PIVR103

COVR1

PIVR104

PIVR105

PIVR102

PIC1701

COC17

PIC1702

COtb0sch1

PIIC504

COIC5:5

PIIC5011

PIIC308

COIC3:3

PIIC304

COP1:2

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