TYPE OF EXHIBIT: USERS MANUAL FCC PART: 2.1033(c)(3) MANUFACTURER: RITRON, INC.
DTX-142 PROGRAMABLE VHF FM TRANSCEIVER MODULE OPERATING AND SERVICE MANUAL RITRON INC.
TABLE OF CONTENTS SECTION TOPIC PAGE 1. DTX-142 SPECIFICATIONS GENERAL RECEIVER TRANSMITTER SUB-D 15 PIN CONNECTOR 2 3 3 4 2. INTRODUCTION GENERAL Model Identification FCC REGULATIONS Licensing Exposure to Radio Frequency Energy FCC Label MAINTENANCE INFORMATION Surface Mount Repairs Precautions for handling CMOS Synthesizer shield 5 5 5 5 6 6 6 7 7 4. DESCRIPTION OF INPUT/OUTPUT 8 5. OPERATION 9 6.
DTX-142 SPECIFICATIONS GENERAL FCC ID: AIERIT17-142 FCC Rule Parts: 90 Frequency Range: 136-156 MHz or 154-174 MHz RF Channels: 8 Independent TX/RX frequencies Synthesizer Step Size: 5 kHz Frequency Stability: +/-2.5 PPM (-30 to +50 C) Tone/Code Signaling: CTCSS (Quiet Call) and DCS Maximum Data rate: 9600 bps with 4-level FSK Power Supply: 8 to 15 VDC Battery Drain: RX Standby: RX Receive: Transmit: 20 mA at 13.8 VDC 250 mA 1 Amp @ 5 Watts at 13.5 VDC Dimensions: 5”H x 3”W x 1.
DTX-142 SPECIFICATIONS RECEIVER Specifications Wide band 25 kHz Narrow band 12.5 kHz Sensitivity (12 dB SINAD): 0.25 µV 0.
DTX-142 SPECIFICATIONS Sub D 15 Pin Connector The DTX-142 is equiped with a 15 pin female sub D connector with the following functions: Pin# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Function least significant channel select bit (CS0) channel select 1 (CS1) Most significant channel select (CS2) Microphone input High/ low power select (pull low to get low power) + 8 to 15 VDC input auxilary input auxilary ouput PC programing port N/A Auxilary monitor input (pull to ground to open squelch) Speaker output Carrier
INTRODUCTION GENERAL RITRON's DTX-142 transceiver module is designed to operate in the VHF band. Two band splits are available, 136-156 MHz (low) or 154-174 MHz (high). The unit supports voice through a microphone input and a nominal 1 watt speaker output. It supports up to 9600 bps 4-level FSK through its auxiliary in and auxiliary out ports. Each radio can be “dealer or factory” programmed to contain a unique set of eight operating frequencies and options.
FCC Label: An FCC label must be visible on the unit as installed in its final configuration. If the unit is to be used as shipped from RITRON, this would be no problem since an FCC label is affixed to the top of the VCO shield. If the DTX-142 is to be installed in an enclosure, the installer must ensure that either the FCC label on the unit is visible through a door, window or other opening, or add a label to the outside of the enclosure.
MAINTENANCE INFORMATION Surface Mount Repair RITRON surface mount products require special equipment and servicing techniques. Improper servicing techniques can cause permanent damage to the printed circuit boards and/or components, which is not covered by RITRON’s warranty. If you are not completely familiar with surface mounted component repair techniques, RITRON recommends that you defer maintenance to qualified service personnel.
DESCRIPTION OF INPUT/OUTPUT Antenna The antenna should ideally be located a least a few feet away from the radio via coaxial cable. The antenna should be installed in such a way that no metal objects other than ground plane metal and no humans are within 43 cm (16.9 in) of the antenna. The installer should confirm there is no RF interference picked up on the analog and digital control lines that run between the transceiver and any other circuitry.
DESCRIPTION OF INPUT/OUTPUT OPERATION Turning the Transceiver On Once power is applied to pin 6 of the radio the microcontroler will start and load the receive frequency of the channel designated by CS2, CS1 and CS0 (pins 3, 2 and 1). The radio will beep out the channel number on the speaker line. Receive The radio will monitor the channel until a carrier becomes present. When an on channel carrier appears, the carrier detect line (pin 13) will be pulled high.
PROGRAMMING THE RADIO PROGRAMMING THE RADIO USING A PC COMPUTER RITRON’s programming kit allows programming of the DTX-142 model radios using a PC compatible computer. An adapter cable DTXP -PAC connects the radio to a computer’s serial communications port. Once the cable is hooked up, the user inserts the diskette provided into his computer’s floppy disk drive and loads a software program. This program transfers data between radio and computer memory, and includes on-screen instructions and help.
DTX-142 THEORY OF OPERATION INTRODUCTION The DTX-142 is an eight-channel synthesized transceiver unit capable of rapid data reception and rapid data transmission at rates up to 9600 bps when using 4-level FSK. The unit maintains under 20 mA current consumption at 13.8 VDC when in the receive standby mode. The current drain goes up as the voltage goes down. The transmitter also exhibits good efficiency. The following table shows typical DTX-142 performance.
The DTX-142 radio is built around a PLL synthesizer that consists of a receive voltage-controlled oscillator (VCO) and transmit VCO. U401 contains both a prescaler and synthesizer controller. The prescaler squares and divides the VCO output present at pin 5 by either 8 or 9, determined by a synthesizer controller logic signal. The prescaler changes once every reference cycle at the appropriate time to yield the right frequency. U401 contains a digital phase detector that works as follows.
Voice and Tone Conditioning in Receiver Three post demodulation paths are provided in the DTX-142. U304c provides DC level translation to bias succeeding op amp stages at about 2.5 volts. The audio path goes through a fourth order 300 Hz high pass filter U305c and d. C326, R353 and R351 de-emphasis the audio. The 1 watt audio amp is turned on by Q311 and Q312. Error tones from come through C325 from pin 13 of U301. The data path goes through U304a and b. U305b is a second order 3000 Hz low pass filter.
MICROCONTROLLER The DTX-142 handheld transceiver is electronically controlled by U301, an 8-bit flash programmable microcontroller. U301 has A/D inputs and PWM outputs for processing analog signals. Radio characteristics are stored in internal EE memory. Its RS232 port is used in programming the radio’s personal characteristics such as frequencies and tones. PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 DESCRIPTION Input is pulled LOW when the PTT input is grounded to initiate transmitter operation.
DTX-142 ALIGNMENT PROCEDURE An authorized RF service technician must perform test and alignment of the DTX-142. Do not attempt service of the DTX-142 if not completely familiar with frequency synthesized radio operation.
DTX-142 ALIGNMENT PROCEDURE TRANSMITTER VOICE & DATA DEVIATION If the transmitter voice deviation needs adjustment perform the following. 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) Set the RF communications test set to the transmit mode. Set audio filtering from <20 Hz to 15 kHz. Set to FM demodulation with +/- peak deviation. Connect oscilloscope to the demodulated output. Select low edge channel on channel select inputs CS2, CS1 and CS0.
Set up for the RSSI squelch is similar except a fixed level, typically –110 dBm, is set on the generator and the RSSI squelch pot R123 is rotated clockwise until it opens. Ambient noise will affect the level at which the RSSI should be set. The squelch level ideally should be done on the desired frequency, in the actual location the radio will be used and connected to the desired antenna. The level should be set high enough to reject most false signals.
