Midland Radio SP-300 service manual RX Tone Demodulation Characteristics

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MAXON

SP-300 HAND HELD

RX TONE DEMODULATION CHARACTERISTICS

SUBAUDIO TONES - CTCSS

Tone Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Hz to 250.3 Hz Non-Standard Tones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Hz to 260 Hz

Due to continuing research and development the company reserves the right to alter these specifications without prior notice.

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May 2001

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Contents Service Manual Table of Contents Board Layout Exploded View Current Consumption SpecificationsTemperature Range GeneralFrequency Bands DimensionsWeight Adjacent Channel PowerPeak Deviation @ 1 kHz Nom. Dev +20dB ReceiverRX Tone Demodulation Characteristics SP-300INTRODUCTION FeaturesBusy Channel Lockout VCO Lock Time Description Description of ControlsDigital Circuits Theory of OperationRF Circuits RF Circuits PLL Synthesizer Speaker Audio Amplifier Squelch mute CircuitKHz Band Pass Filter Noise DetectorTo replace the belt clip Maintenance and RepairRemoving & Replacing the Belt Clip Removing the belt clipTo remove the PTT assembly Removing & Replacing the BatteryTo remove the battery To replace the batteryRemoving & Replacing the Antenna & Control Knobs Removing & Replacing the ACCES- Sory ConnectorTo remove the Back Cover Removing & Replacing the Back CoverTo replace the Back Cover To remove the Main Board Removing & Replacing the Main BoardTo replace the Main Board Removing & Replacing the DAUGH- TER Boards Component ReplacementRemoving & Replacing the Speaker Surface Mounted Integrated Circuit Replacement Surface Mount Component ReplacementProgramming Alignment ProcedureCloning RX VCO S.G. @ 1kHz Audio Test Equipment SetupTP1 Alignment Points DiagramSymptoms Causes Counter Measures Troubleshooting GuideMain Circuit Voltage ChartsReceive State Transmit State REF# Description PART# SP-300 Series UHF & VHF Digital Section Parts List-30- May REF # Description Replacement Modules SP-300 Series VHF RF Section Parts List-32- May -33- May SP-300 Series UHF RF Section Parts List -35- May -36- May -37- May KTA1504SY Component Pinout-39- May Base Diagram PIN Description UHF FRONT-END VHF Power AMPUHF Power AMP VHF FRONT-ENDUHF V.C.O VHF V.C.OTcxo ACC-200 BatteryFuse SP-300 Series VHF RF Schematic UHF RF Schematic -47- May Board Layout Top Main Board Assembly 416121B -49- May