EFJohnson 7780 service manual Receiver Performance Tests

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ALIGNMENT PROCEDURE AND PERFORMANCE TESTS

PERFORMANCE TESTS

6.8 RECEIVER PERFORMANCE TESTS

6.8.1 PRELIMINARY SETUP

This transceiver does not have a special test mode that can be selected to perform testing. Therefore, temporary conventional channels are programmed to perform this function. Program channels near the low, middle, and high ends of the band (wideband, narrow band or both) and with and without Call Guard (CTCSS/DCS) squelch as applicable. In addition, to check high and low power and talk-around operation, program High/Low Power and Repeater Talk-Around option switches. Proceed as follows to check receiver operation:

1.Select the channel near the center of the band (around 860 MHz).

2.Connect the signal generator to the antenna jack (see Section 6.1.2 for more information). Set the output to the channel frequency, modulated with 1 kHz at 3 kHz (wideband channels) or 1.5 kHz deviation (narrow band channels).

6.8.2 SINAD SENSITIVITY

NOTE: The audio output level of the accessory con- nector is at a lower level than at the internal speaker. In addition, the internal speaker automatically mutes when a load of approximately 1k ohm or less is con- nected to this output.

1.Connect a SINAD meter to the speaker output of the RPI (see Section 6.1.2).

2.Decrease the signal generator output to obtain a 12 dB reading on the SINAD meter. The signal gener- ator output should be 0.35 µ V maximum. If required, temporarily readjust squelch for “0” as described in Section 6.6. (after clicking “Read Tune Settings” to note the current setting).

3.Check both wide and narrow band channels if appli- cable, and also check the channels on each end of the band. Reset the squelch to the previous level if it was changed.

6.8.3 SQUELCH SENSITIVITY

With the test setup used for the preceding test, slowly increase the signal generator output until the squelch just opens (audio is enabled). Then decrease the signal generator output until it just closes. The squelch should open after 12 dB SINAD and close before 6 dB SINAD.

6.8.4 AUDIO POWER AND DISTORTION

CAUTION

Grounding either speaker terminal may damage the audio amplifier. Therefore, make sure that any meter connected across the speaker has floating inputs.

To measure audio output power, the actual level across the speaker must be measured because full output power is not available at the accessory connector. If a load of approximately 1k ohm or less is connected to the speaker output of the accessory connector, it must be disconnected to enable the internal speaker. Proceed as follows:

1.Remove the transceiver cover and connect power as described in Section 6.1.6. Carefully turn the front cover over to access the speaker.

2.Connect an AC voltmeter and distortion meter across the speaker (make sure they have floating inputs). Alternatively, 100 µ F, non-polarized capac- itors can be used in series with the leads.

3.Set the signal generator output for –60 dBm (220 µ V). Minimum audio power should be 0.5 watt across the 16-ohm speaker (2.8 V rms). Distortion should be less than 5% at 0.5 watt.

6.8.5 RECEIVER CURRENT DRAIN

Maximum transceiver current with 0.5-watt audio output is 300 mA. With the receiver squelched, it should be 92 mA maximum.

November 1999

 

Part No. 001-7780-500

6-6

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Contents 7780 Page Page Table of Contents Table of Contents CONT’D List of Tables List of FiguresGeneral Information Scope of Manual Equipment DescriptionPart Number Breakdown AccessoriesFactory Customer Service Transceiver IdentificationToll-Free 800 AccessoriesAccessory Factory ReturnsInternet Home Intrinsically Safe Information Replacement PartsDefinitions Intrinsically Safe and Nonincendive Ratings Temperature Code T3CPossible Ignition Sources Classification of Hazardous Areas and AtmospheresTypical Hazard Group Class Accessing PC BoardsMaterial Classification Area ClassificationRemoving RF Unit Removing Logic UnitSpecifications GeneralTransceiver Operation FeaturesControls and Display TX Indicator Red Indicates when the transmitter is keyed Low-Battery Indicator AmberFront Panel Keys Full Keypad Model DisplayDisplay General Operation Turning Power on and Setting VolumeOption Switches BacklightFunction Conv Option Switch FunctionsSee Tone ENABLE/DISABLE ScanningConventional and SMARTNET/ Smartzone Operation Display Mode Selection Conventional FeaturesMonitoring Before Transmitting Busy Channel Lockout Monitor ModeCall Guard Squelch Power Output Select Penalty TimerConversation Timer Conventional Mode ScanningPriority Channel Sampling DTMF/ANI Signaling Standard Conventional CallsStandard Group Calls SMARTNET/SMARTZONE FeaturesViewing Unit ID Enhanced Private Conversation CallsTransceiver Operation Private Conversation II Calls Telephone Calls Call Alert Messaging Emergency Alarm and CallSending Status Conditions SMARTNET/SMARTZONE Scanning Failsoft OperationDynamic Regrouping Supervisory Tones Menu Description Keypad ProgrammingZone Change Parameter System Parameters Channel Change ParameterChannel Parameters Transceiver Programming Programming SetupPctrunk Software Installation Computer DescriptionProgramming File Types Connecting RPI to Computer and TransceiverStarting and Exiting Help FilesFile Size Indication Screen Pop-Up Buttons and File Size IndicatorProgramming Procedure Creating and Displaying SystemsMenu Commands Menu BarSystems Menu Radio Type MenuDownload Menu Upload Menu Window MenuBand DefaultsRADIO-WIDE Parameter Screens ZonesModify List Screen Radio Wide Scan ListRadio-Wide Scan List Screen Assign Function ButtonsFull Spectrum CC Scan RADIO-WIDE Conventional ScreenRADIO-WIDE SMARTNET/SMARTZONE Screen Hot DtmfProgramming Conventional Systems and Channels Adjustable ParametersRADIO-WIDE Portable Options Screen Conventional System General ScreenKeypad Editing TimersConventional System Modify Scan List Screen Scan List ButtonSetting UP Conventional Channels Scan TimersPriority Channel Selection Conventional Channel Screen Parameters Selected ChannelChannel Type Transmit PowerSignaling Tx Time-OutISW Delay Time Restricted AccessTime-Out Timer Splinter ChannelsPhone Interconnect SMARTNET/SMARTZONE System Other ID’S ScreenSMARTNET/SMARTZONE System Phone Interconnect Screen Private CallSMARTNET/SMARTZONE System Talk Groups Screen SMARTNET/SMARTZONE System Emergency Settings ScreenEmergency Alarm Failsoft ChannelTrunking Phone List Screen SMARTNET/SMARTZONE System Lists ScreensMessage Aliasing Screen Announcement Groups Screen Control Channels ScreenTrunking Call List Screen Status Aliasing Screen Setting UP SMARTNET/SMART- Zone ChannelsSMARTNET/SMARTZONE Channel Screen Parameters SMARTNET/SmartZone Channel Screen Other Screen ParametersCall Guard CTCSS/DCS Codes and Tones Recommended Tone Call Guard Codes FreqMHz Channels MHz Channels MHz Channels MHz Channels MHz Channels MHz Channels Circuit Description Power Switching and RegulationPower Switching Synthesizer DescriptionSynthesizer Chip IC1 VCO and Tcxo ModulationCharge Pump Q1, Q2, Loop Filter RF Amplifier Q1, First Mixer Q2 Receiver Circuit DescriptionIf Amplifier Q2, LIMITER/DETECTOR IC3 Transmitter Description Antenna Switch and LOW-PASS FilterSquelch Circuit IC4A/B, IC5A Amplifier Q9, Driver Q8Control Logic and Display Receive Audio ProcessingMicroprocessor IC306 Pin Descriptions Pin Port Name Input or Description Active High OutputHvfulswlrq Receive and Transmit Data Processing Audio Amplifier IC104-IC106Receive Data FILTER/DETECTOR IC102A/B, IC107A/B Transmit Data Filter IC206B/ IC206A Transmit Audio ProcessingLOW-PASS Filter IC205A/B Smartnet Data ProcessingPower Setting Operating Time Battery Pack and Charger InformationBattery Pack Function Fahrenheit CelsiusBattery Pack and Charger Information Alignment Procedure and Performance Tests Test SetupTune Software Hqhudo Mm/3/32 Mm/1/8 Phone JackPreliminary Setup Main Pctune ScreenHigh Power Level = 3.0 watts Low Power Level = 1.0 watt Transmit Frequency and PowerTransmit Power Adjustment Screen Modulation BalanceAudio Deviation Squelch AdjustRssi Adjust Data DeviationPerformance Tests Receiver Performance TestsTransmit Frequency Power OutputTransmitter Performance Tests Transmit ModulationThis page intentionally left blank Chassis Parts Parts ListDisplay Assembly Ref No DescriptionKEY Assembly Display AssemblyKEY Assembly If AssemblyIf Assembly PLL Assembly RF UnitRF Unit NJM2904V-TE1 IC RF Unit Logic Unit Logic Unit TDA7233D IC Logic Unit 200K ERJ3GE MP35 MP18 MP25 KEY Front Panel EP2EP1 MP32 MP33 MP27 MP34 MP28 MP29 MP23 MP22 MP30 MP24 MP26 MP18 PLL Board TOP View Schematic Diagrams and Component LayoutsPLL Board Bottom View If Board TOP View If Board Bottom ViewTransceiver Block Diagram RF UnitRF Board TOP View MICRF Board Schematic If AMPLogic Board TOP View HD1Logic Board Schematic Receive Audio ProcessingDisplay Board Bottom View GND KEYR3 KEYR2 KEYR1 KEYR0 KEYS3 KEYS2 KEYS1 KEYS0 GNDDisplay Board Schematic DS3 DS4 DS5KEY Board Front View KEY Board Back ViewKEY Board Schematic S S R R R RScan HC2 HC7 HC8 HC3 Schematic Diagrams and Component Layouts
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