ACU BOOTCAMP - APAN Community

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ACU BOOTCAMPACU BOOTCAMPACU BOOTCAMPACU BOOTCAMPOPTIMIZING THE DSP MODULEOPTIMIZING THE DSP MODULEOPTIMIZING THE DSP MODULEOPTIMIZING THE DSP MODULE

I Can’t hear you…!!

PRESENTER:

– Roman W. KalutaPublic Safety Liaison – Customer Advocate

(919) 608-8409

[email protected]

AGENDA:

– Become experts at align an ACU land-mobile radio interface. This bootcamp is applicable to the following:� DSP-1 module

� DSP-2 module

� DSP-3 module

� ACU-M Resource Port

� ACU-5000 Radio Channel

� NXU-2 & NXU-2A Modules

ACU BOOTCAMP:

OPTIMIZING THE DSP MODULE

Capabilities – Communications Interoperability

• Localized / Wide Area Interoperability Gateways

• Standards-Based Telephony Interfaces

• Analog PSTN

• Digital SIP

• Digital RTP

• Cellular / 4G / LTE

• Satellite

• JPS VIA PTTOC

Channels: up to 24 (modular)

Interfaces: Radio, PSTN, SIP, RoIP

Wide Area Interop System Capable

Channels: up to 24 (non-modular)



Channels: up to 5 (modular)



Channels: up to 4 (non-modular)

Interfaces: Radio, RoIP


Channels: 80 (modular)

Interfaces: Radio, PSTN, SIP, RTP, RoIP,

LTE


Channels: 2 (non-modular)

Interfaces: Radio, PSTN, SIP, RTP, RoIP,

LTE


ACU-2000

ACU-5000

ACU-T

ACU-M

ACU-Z1

RSP-Z2

ACU Gateway

INTRODUCTION:

DSP MODULE

ACU BOOTCAMP:


ACU BOOTCAMP:


• The DSP-2 Module is the primary interface module for 4-wire or 2-wire land mobile radios,

control stations or analog dispatch consoles

• The DSP-2 module contains a Digital Signal Processor (DSP) hybrid chip that is

adjusted by the operator to support different types of donor radios. The DSP allows different

radios to operate in an neutral manner without regards to:

� Frequency Band

� Modulation Technique

� Protocol

� Encryption

DSP-2 MODULE DESCRIPTION

ACU BOOTCAMP:


UHF Repeater

Two DSP-2 Modules

Cross-Connected

VHF

Donor Radio

UHF

Donor Radio

VHF Repeater

COR PTT

Receive Audio + COR Transmit Audio + PTT


CROSS-CONNECTION

ACU BOOTCAMP:


DSP-2 Module Cross-Connected to

HSP-2A Module

VHF

Donor Radio

VHF Repeater

COR

Local

Operator

Handset


CROSS-CONNECTION

ACU BOOTCAMP:


“Standard“ DSP-2 Module Cross-

Connected to “Hybrid” DSP-2 Module

VHF

Donor Radio

VHF Repeater

COR

RoIP

800 MHz

Donor Radio

PTT

NETWORK

800 MHz

Standard Mode Hybrid Mode


CROSS-CONNECTION

ALIGNMENT OF THE

DSP MODULE

ACU BOOTCAMP:


• Different Donor Radio assets have varying

performance characteristics, even radios of

similar model numbers

• The supporting DSP-2 module must be

aligned to compensate for those differences

� Over- or Under- modulating cross

connected assets

� Loss of first syllable or entire words

� Unable to reply to allied agency or unit

� Disruptive “ping-pong” between donor

radios

� Radios in the field become unusable

ALIGNMENT OF DSP-2 MODULE

WHY ALIGN ???

Donor Radio

Donor Radio

Effects of Misaligned DSP Module

ACU BOOTCAMP:



BEGIN DSP-2 ALIGNMENT BY LOADING TEMPLATE

Donor Radio

Double-Left-Click on Module Icon to open Module Settings console

Choose the Template based upon the

Manufacturer & Model Number of the Donor Radio

Asset

ACU BOOTCAMP:


ETHERNET

COR

LINK

ACTIVE

SCM-2

SIGNAL

PTT

FAULT

ETHERNET

COR

LINK

ACTIVE

SCM-2

SIGNAL

PTT

FAULT

ETHERNET

COR

LINK

ACTIVEACTIVE

LINK

SCM-2

O2 O3 O4 O5 O6 O7 O8 O9 10

DSP-2 IP

FAULT

SIGNAL

ETHERNET

ACTIVE

PTT

COR

LINK

DSP-2 IP

FAULT

SIGNAL

ETHERNET

ACTIVE

PTT

COR

LINK

DSP-2 IP

FAULT

SIGNAL

ETHERNET

ACTIVE

PTT

COR

LINK

SCM-2

SIGNAL

PTT

FAULT

OO

VOLUME

SPEAKER

OFF

HANDSET

PTT

FAULT

SIGNAL

DEFABC

OPER

TUV

JKL

4

PRS

7

GHI

1

O

5 6

8

WXY

9

2

MNO

3

HSP-2 IP

EAR

CPM-6

HANDSET

EXP

MASTER

FAULT

ETHERNET

CPM-6

O1

LINK

ACTIVE

ETHERNET

COR

PTT

SIGNAL

FAULT

DSP-2 IP

ACU-2000 IP

+12V

POWER

-12V

AC

DC

PSM-1 IP PSTN-2

L1

RING

MON

CONNECT

FAULT

VOX

MON

LP-1 IP

RING

P1

P2

VOX

OFF HOOK

FAULTFAULT

PTT

SIGNAL

COR

ETHERNET

• The HSP-2 Module AUDIO LINE LEVEL specifications defines the operational

“Sweet Spot” of the entire ACU Chassis:

� INPUT AUDIO LEVEL: 0 dBm fixed, nominal (not adjustable)

� OUTPUT AUDIO LEVEL: 0 dBm fixed, nominal (not adjustable)

• Since the HSP-2 gain levels cannot be adjust or changed , the HSP module is an

ideal Alignment Standard (0 dBm)


USING HSP MODULE AS AN ALIGNMENT STANDARD

ACU BOOTCAMP:



USING HSP MODULE AS AN ALIGNMENT STANDARD

PSM-1A HSP-2

+12V

-12V

POWER

AC

DC

JPS Communications, Inc

ACU-1000

VOLUME PHONES HANDSET

PTT

FAULT FAULT

SPEAKER

OFF SLAVE

MASTER

CPM-2

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1 AP-1

MON RING

MON

BYPASS

COR

NORMAL

PEAK FAULT

VOX

P1

P1

OFF HOOK

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

LP-1 PSTN-1 PSTN-1

Donor Radio

During the alignment process, the DSP should be cross connected with

the HSP “Standard”

Avoid aligning a DSP against another “unknown” DSP

ACU BOOTCAMP:


ALIGNMENT OF DSP-2 MODULE / RECEIVE AUDIO LEVEL

Donor Radio

RXTX

• Important DSP-2 Receive Parameters

� RX INPUT AUDIO LEVEL:

+12 to -26 dBm

� RX INPUT AUDIO DELAY:

20 msec to 300 msec

When the Donor Radio is receiving, RX parameters in the DSP module setting

screen should be addressed

This is the audio level coming from the Donor Radio

ACU BOOTCAMP:


PSM-1A HSP-2

+12V

-12V

POWER

AC

DC


ACU-1000


PTT

FAULT FAULT

SPEAKER

OFF SLAVE

MASTER

CPM-2

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1 AP-1

MON RING

MON

BYPASS

COR

NORMAL

PEAK FAULT

VOX

P1

P1

OFF HOOK

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

LP-1 PSTN-1 PSTN-1

Donor Radio

• The RX AUDIO LEVEL adjustment value in the

module setting screen is the amount of audio coming

from the radio

• The DSP-2 module will add the appropriate amount of

gain or attenuation to achieve the desired 0 dBm level

• Use the [Bracketed] value as a gain control: The

higher the bracketed number, the higher the gain

(volume)

Adjust the DSP-2 RX AUDIO LEVEL until

the signal LED flashes with each

syllable

ALIGNMENT OF DSP-2 MODULE / RECEIVE AUDIO LEVEL

RX

ACU BOOTCAMP:


ALIGNMENT OF DSP-2 MODULE / TRANSMIT AUDIO LEVEL

Donor Radio

RX

• Important DSP-2 Transmit Parameters

� TX OUTPUT AUDIO LEVEL:

+12 to -26 dBm

� TX OUTPUT AUDIO DELAY:

0 msec to 800 msec

1600 msec (doubled)

When the Donor Radio is transmitting, TX parameters in the DSP module

setting screen should be addressed

This is the audio level going to the Donor Radio from the DSP-2

TX

ACU BOOTCAMP:


PSM-1A HSP-2

+12V

-12V

POWER

AC

DC


ACU-1000


PTT

FAULT FAULT

SPEAKER

OFF SLAVE

MASTER

CPM-2

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1 AP-1

MON RING

MON

BYPASS

COR

NORMAL

PEAK FAULT

VOX

P1

P1

OFF HOOK

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

LP-1 PSTN-1 PSTN-1

Donor Radio

• The TX AUDIO LEVEL adjustment value in the

module setting screen is the amount of audio that is

being delivered to the radio

• The DSP-2 module will add the appropriate amount of

audio gain to properly “Modulate” the radio (pre-amp)

• Use the [Bracketed] value as a gain control: The

higher the bracketed number, the higher the gain

(volume)

Adjust the DSP-2 TX AUDIO LEVEL until

audio level in the field is satisfactory


TX

ACU BOOTCAMP:


PSM-1A HSP-2

+12V

-12V

POWER

AC

DC


ACU-1000


PTT

FAULT FAULT

SPEAKER

OFF SLAVE

MASTER

CPM-2

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1 AP-1

MON RING

MON

BYPASS

COR

NORMAL

PEAK FAULT

VOX

P1

P1

OFF HOOK

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

LP-1 PSTN-1 PSTN-1

Donor Radio

• By using an additional radio in the field, the ACU’s TX

Audio Level can be adjusted such, that its level matches

the additional radio in the field

• The additional radio is considered a, “Standard”

The ACU audio level heard in the field should be at the same level as….

…other radios in the field


TX

ACU BOOTCAMP:


ALIGNMENT OF DSP-2 MODULE / RECEIVE AUDIO DELAY

Donor Radio

TX

• Important DSP-2 Receive Parameters

� RX INPUT AUDIO LEVEL:

+12 to -26 dBm

� RX INPUT AUDIO DELAY:

20 msec to 300 msec

When the Donor Radio is receiving, RX parameters in the DSP module setting

screen should be addressed

RX Audio Delay is the audio being “buffered” or “stored” within the DSP-2

module prior to a COR event

RX

ACU BOOTCAMP:


PSM-1A HSP-2

+12V

-12V

POWER

AC

DC


ACU-1000


PTT

FAULT FAULT

SPEAKER

OFF SLAVE

MASTER

CPM-2

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1 AP-1

MON RING

MON

BYPASS

COR

NORMAL

PEAK FAULT

VOX

P1

P1

OFF HOOK

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

LP-1 PSTN-1 PSTN-1

Donor Radio

• The Digital Signal Processor inside of the DSP-2

Module is a processor that introduces “Process Delays”

which could possibly result in the loss of the first

syllables of the interoperable communications

• To compensate for the “Process Delay”, the DSP-2

Module is continually storing audio in preparation of a

COR event (RX)

• The buffering process will ensure that the leading

syllable is retained

handset is complete

WHEN TO ADD RX AUDIO DELAY?

Increase the RX AUDIO DELAY until the resulting audio heard at the HSP

handset is complete

…..1, 2, 3, 4, 5

ResultTest, 1, 2, 3, 4, 5

Source

ALIGNMENT OF DSP-2 MODULE / RECEIVE AUDIO DELAY

RX

ACU BOOTCAMP:


ALIGNMENT OF DSP-2 MODULE / TRANSMIT AUDIO DELAY

Donor Radio

RX

• Important DSP-2 Transmit Parameters

� TX OUTPUT AUDIO LEVEL:

+12 to -26 dBm

� TX OUTPUT AUDIO DELAY:

0 msec to 800 msec

1600 msec (doubled)

When the Donor Radio is transmitting, TX parameters in the DSP module

setting screen should be addressed

TX Audio Delay is audio “buffered” or “stored” within the DSP-2 module prior

to transmission

TX

ACU BOOTCAMP:


Trunk Radio User

WHAT IS A TRUNK RADIO SYSTEM?

Trunk Radio User

• TRUNK RADIO SYSTEMS

automatically and dynamically

allocates of a small number of

channels among a large number

of radio users

Trunk Radio System

Trunk Radio User

• When a trunk radio user presses his PTT button on his radio,

the TRUNKING CONTROLLER:

a. Analyzes the capacity of the channels

b. Selects the least congested channel

c. Assigns the channel to all radios within the talkgroup

d. Originating user hears the “Permit to Talk” tone

e. User can begin conversation

• Granting of the channel is a Process Delay that will result in

the loss of the first syllables of the interoperable conversation

TX

ACU BOOTCAMP:



TRANSMIT AUDIO DELAY

PSM-1A HSP-2

+12V

-12V

POWER

AC

DC


ACU-1000


PTT

FAULT FAULT

SPEAKER

OFF SLAVE

MASTER

CPM-2

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1 AP-1

MON RING

MON

BYPASS

COR

NORMAL

PEAK FAULT

VOX

P1

P1

OFF HOOK

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

LP-1 PSTN-1 PSTN-1

Trunk Donor Radio

…..1, 2, 3, 4, 5

ResultTest, 1, 2, 3, 4, 5

SourceTrunk Radio

System

• When the HSP Operator presses his Handset PTT, the Donor Trunk Radio will

immediately key. This will assure that the trunk radio system quickly settles

• …however, the HSP Operator’s audio is “buffered” or

“stored” inside the DSP-2 for a duration that is equal to,

or longer than the Channel Acquisition time of the trunk

radio system

WHEN TO ADD TX AUDIO DELAY?

Increase the TX AUDIO DELAY until the resulting audio stream heard at the radio in the field is complete

TX

ACU BOOTCAMP:


ALIGNMENT OF DSP-2 MODULE / COR SQUELCH TYPE (COR)

TX

• In some instances when the Donor Radio is in a

RECEIVE-STATE it will generate a COR Signal which

can be used to alert the DSP-2 module that its Donor

Radio is in the RX-state

• The Hardwired COR squelch type is most desirable

because the DSP-2 will immediately react to the

receiver. This will reduce the chances of truncating

leading syllables in the communications stream

AU

DIO

CO

R

COR LED will light when Donor Radio is in a RX-State

Hardwire COR is ideal because the radio is

determining when the Donor Radio is receiving

RX

ACU BOOTCAMP:


ALIGNMENT OF DSP-2 MODULE / COR SQUELCH TYPE (VOX)

TX

• When a Donor Radio does not have the ability to

produce a Hardwire COR control signal when its

receiver fully-quiets, the VOX COR Squelch Type

should be used (Derived Squelch Type)

• VOX is triggered when ANY audio is delivered to the

DSP-2 module

• VOX will work with ALL Donor Radios, but in some

cases, might not be ideal

AU

DIO

COR LED will light when DSP detects ANY audio from the

Donor Radio

VOX introduces process delay that may result in the loss of

leading syllables. Add a bit of RX Audio Delay will help

RX

ACU BOOTCAMP:


SSB AM Radio

• When the Donor Radio is difficult to squelch, VOX Squelch Type should not be used

• Instead, VMR COR Squelch Type (Voice Module Recognition) will initiate a COR Event in

the presence of HUMAN SPEECH, only


SINGLE SIDE BAND DONOR RADIOS

SSB AM Radio

?

?

?

?

Many Single Side Band (SSB) radios are

difficult to squelch, and are constantly

intrinsically “noisy”

…as a result, disparate radios in the field will be in a CONSTANT receive-state, and unusable

PSM-1A HSP-2

+12V

-12V

POWER

AC

DC


ACU-1000


PTT

FAULT FAULT

SPEAKER

OFF SLAVE

MASTER

CPM-2

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1 AP-1

MON RING

MON

BYPASS

COR

NORMAL

PEAK FAULT

VOX

P1

P1

OFF HOOK

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

LP-1 PSTN-1 PSTN-1

If the DSP-2 COR Squelch Type is VOX, COR EVENT will be CONSTANT…

RX

ACU BOOTCAMP:


ALIGNMENT OF DSP-2 MODULE / COR SQUELCH TYPE (VMR)

TX

• DSP-2 modules that host Donor Radio that are

difficult to squelch (i.e. SSB, aviation, AM. HF radios),

VMR COR Squelch Type should be used

• VMR (Voice Modulation Recognition) is extremely

DSP processor intensive, and which could result in loss

of leading syllables in the communication stream

AU

DIO

COR LED will light when DSP detects HUMAN SPEECH audio

from the Donor Radio

VOX introduces process delay that may result in the loss of

leading syllables. Add a bit of RX Audio Delay will help

RX

ACU BOOTCAMP:



VOX – VMR HANGTIME

PSM-1A HSP-2

+12V

-12V

POWER

AC

DC


ACU-1000


PTT

FAULT FAULT

SPEAKER

OFF SLAVE

MASTER

CPM-2

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1 AP-1

MON RING

MON

BYPASS

COR

NORMAL

PEAK FAULT

VOX

P1

P1

OFF HOOK

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

LP-1 PSTN-1 PSTN-1

Donor RadioTest, 1, 2, 3, 4, 5

Slow Test Count

• Since VOX and VMR COR Squelch

Types are process intensive, there is

always a possibility that the resulting

shared audio will be missing the

leading syllables of each COR event

w/o VOX / VMR Hangtime

w/ VOX / VMR Hangtime

Caution: Using too much VOX VMR Hangtime will block the reply from

disparate communications so long as the COR Event is present

RX

ACU BOOTCAMP:



VOX – VMR THRESHOLD

PSM-1A HSP-2

+12V

-12V

POWER

AC

DC


ACU-1000


PTT

FAULT FAULT

SPEAKER

OFF SLAVE

MASTER

CPM-2

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1

FAULT

PTT

SIGNAL

COR

MON

DSP-1 AP-1

MON RING

MON

BYPASS

COR

NORMAL

PEAK FAULT

VOX

P1

P1

OFF HOOK

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

RING

MON

L1

L2

CONNECT

VOX

FAULT

LP-1 PSTN-1 PSTN-1

Donor Radio

• Depending upon the environment VOX or VMR

Threshold can be adjusted to make the COR event

trigger more easily or less easy

• VOX Threshold:

� Low = Quiet Environment

� High = Noisy Environment

• VMR Threshold:

� Low = Trigger on less voice attributes

� High = Trigger more voice attributes

Noisy Environment: Radio operator speaking above the ambient noise (i.e. inside aircraft, near generator, etc)

Quiet Environment: Radio operator speaking quietly (i.e. surveillance, throat MIC, SCUBA, etc)

RX

ACU BOOTCAMP:


Release PTT

WHAT IS SQUELCH TAIL?

Repeater

• What happens to the repeater when a radio operator Presses PTT Button?

1) Receiver at repeater notices the user is transmitting

2) The repeater’s transmitter turns-ON, and stays on as long as radio user keys radio

• What happens to the repeater when the radio operator Releases PTT Button?

1) Receiver senses that the user is no longer transmitting

2) Transmitter stays ON for a short period of time (aka, Hangtime, Squelch Tail)

3) User’s radio is now eligible to receive

4) If Hangtime duration is long, the user’s radio will “hear” (receive) a short white

noise burst from the repeater

SQUELCH TAIL is the short burst of white noise heard on a radio after the radio operator

releases PTT button

Note: A Courtesy Tone or a radio-to-radio Handshake can sometimes be heard on a radio after the PTT button is released

ACU BOOTCAMP:


Repeater Repeater


…AND HOW DOES IT AFFECT THE ACU?

When operator presses or releases the radio’s PTT button, he is virtually,…

…activating and deactivating the disparate Donor Radio’s transmitter

The SQUELCH TAIL from the repeater will affect the Donor Radio after its

completed its transmission

TX

TX

ACU BOOTCAMP:


Repeater Repeater

The DSP-2 module will COR as a result of the Squelch Tail, and will deliver the

“White Noise” burst to the cross connected Donor Radio…

RX

…if the disparate Repeater also has a long-duration Squelch Tail, the two radio systems

will begin PING-PONG’ing

RXRXRX

RX

!

Once the PING PONG begins it will not stop until the cross connection is disbanded.

More importantly, the radios in the field will not be able to transmit due the “oscillation” between the repeater sites


…AND HOW DOES IT AFFECT THE ACU?

TX TX

ACU BOOTCAMP:


Repeater Repeater

Add COR INHIBIT TIME AFTER PTT to DSP-2 Modules that are suspected of inducing the Ping Pong

RX

RXRXRX

RX

COR INHIBIT TIME AFTER PTT will force the DSP-2 to “Inhibit” detection of COR after the Donor Asset terminates a

transmission


COR INHIBIT TIME AFTER PTT

MITIGATE PING-PONG

! NOTE: Excessive COR INHIBIT TIME AFTER PTT may

“block” radio talk-back

TX TX

ACU BOOTCAMP:


Repeater Repeater

As an alternative….

Change the COR SQUELCH TYPE to VMR

COR will not be derived because the SQUELCH TAIL does not contain HUMAN SPEECH, thus COR will be derived

RX

RXRXRX

RX


COR INHIBIT TIME AFTER PTT

MITIGATE PING-PONG

TX TX

ACU BOOTCAMP:



How to Determine Ping-Pong Before it Becomes a Problem?

Repeater with LONG HANGTIME

PTT Pressed

PTT Released

PTT Pressed

PTT Released

Press & Release Handset PTT

Button

Press & Release Handset PTT

Button

COR Indicator does not appear after PTT button is released. Ping Pong is not an issue

Repeater with SHORT HANGTIME

COR Indicator appears momentarily after PTT button is released. Ping Pong might become a problem

TX

TX

ACU BOOTCAMP:


Repeater Repeater

Noisy Reduction Value ranges from:

OFF to Maximum “9”


NOISE REDUCTION VALUE

Noisy Radio

System

• Noise Reduction Value can be applied to the DSP-2

module to help suppress the noise received from a

“Noisy” radio system

• Noise Reduction Value will not prevent noise being

transmitted by the transmitting donor asset

RX

TX

DONOR RADIO

ANTENNA MANAGEMENT

ACU BOOTCAMP:


Who’s car is this…?

You…..Drop and give me 10….now…!

ACU BOOTCAMP:


• It is very common to have Donor Radio assets positioned within close proximity to one

another

• If the transmit power of a Donor Asset is too high, it may interact with the receivers of the

adjacent Donor Assets, de-sensitizing their receivers…..regardless of frequency band or

protocol

DONOR RADIO ANTENNA SEPARATION

PRC-150

150 WATTSDe-sensing

Hint: All COR LED’s will light if Donor Radio receivers are

de-sensing

TX

ACU BOOTCAMP:


DONOR RADIO ANTENNA SEPARATION

Horizontal Separation

Vert

ical

Separa

tion

1) Move antennas vertically (mast, tower)

2) Move antennas horizontally (cable)

3) Reduce transmitter power (enough to

reach repeater, if applicable)

How to Prevent De-Sensing:

Due the characteristic radiation pattern of a

dipole antenna, vertical separation is less

than horizontal separation

PRC-150

150 WATTS

TX

Congratulations, private, You’ve earned

your stripe...

Now go out n’ make me proud….!!!!!!

ACU BOOTCAMPACU BOOTCAMPACU BOOTCAMPACU BOOTCAMPOPTIMIZING THE DSP MODULEOPTIMIZING THE DSP MODULEOPTIMIZING THE DSP MODULEOPTIMIZING THE DSP MODULE

42

Contact Information

Roman Kaluta, Customer Advocate

[email protected]

Lee Martin, DOD - [email protected]

919.410.1131

Customer Technical Support

[email protected]

24/7 Support = (800) 543.2540www.jpsinterop.com

JPS Interoperability Solutions, Inc.5800 Departure Drive

Raleigh, North Carolina 27616(919) 790.1011

ACU BOOTCAMP - APAN Community

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