Assessments - 2, GPA: 4
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Facilidade de uso
• Uses “state of the art” digital electronic filtering for superior noise free sound! Speech inversion type system - similar to SSB. • Decodes most cordless phones and basic 2-Way radio systems • Loud, amplified speaker output - no need for an external amp! • Super clean, low noise audio - excellent audio quality! • Accepts mike, line, or speaker level inputs. • Handy phono type input and output connections. • Operates on 9 to 15 volts DC. • Super easy hook-up with pushbutton “bypass” mode. Switch from scramble/descramble to feed through without moving wires! • Informative manual answers questions on theory, hookups and uses - enhances resale value, too! • Add our custom case and Knob set for a finished “Pro” look. RAMSEY TRANSMITTER KITS • FM100B Professional FM Stereo Transmitter • FM25B Synthesized Stereo FM Transmitter • MR6 Model Rocket Tracking Transmitter • TV6 Television Transmitter RAMSEY RECEIVER KITS • FR1 FM Broadcast Receiver • AR1 Aircraft Band Receiver • SR2 Shortwave Receiver • SC1 Shortwave Converter RAMSEY HOBBY KITS • SG7 Personal Speed Radar • SS70A Speech Scrambler • BS1 “Bullshooter” Digital Voice Storage Unit • AVS10 Automatic Sequential Video Switcher • ECG1 Heart Monitor • WCT20 Cable Wizard Cable Tracer • LABC1 Lead Acid Battery Charger • LC1 Inductance-Capacitance Meter RAMSEY AMATEUR RADIO KITS • DDF1 Doppler Direction Finder • HR Series HF All Mode Receivers • QRP Series HF CW Transmitters • CW7 CW Keyer • CPO3 Code Practice Oscillator • QRP Power Amplifiers RAMSEY MINI-KITS Many other kits are available for hobby, school, Scouts and just plain FUN. New kits are always under development. Write or call for our free Ramsey catalog. SS70A SPEECH SCRAMBLER KIT INSTRUCTION MANUAL Ramsey Electronics publication No. MSS70A Revision 1.3 First printing: September 1995 COPYRIGHT .1995 by Ramsey Electronics, Inc. 590 Fishers Station Drive, Victor, New York 14564. All rights reserved. No portion of this publication may be copied or duplicated without the written permission of Ramsey Electronics, Inc. Printed in the United States of America. SS70A • 2 Ramsey Publication No. SS70A Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR SPEECH SCRAMBLER / DESCRAMBLER KIT TABLE OF CONTENTS Introduction to the SS70A............. 4 Circuit Description ......................... 5 Parts List ....................................... 7 Schematic Diagram....................... 8 SS70A Assembly instructions ....... 9 Testing the SS70A ....................... 12 Hook-up Configurations ............... 13 Troubleshooting ........................... 16 Parts Layout Diagram .................. 18 Ramsey Kit Warranty................... 19 RAMSEY ELECTRONICS, INC. 590 Fishers Station Drive Victor, New York 14564 Phone (585) 924-4560 Fax (585) 924-4555 SS70A • 3 INTRODUCTION The Ramsey SS70A is a complete two-way speech scrambler/descrambler with suitable inputs and outputs for scanner, two-way radio, cordless telephone, or tape recorder operation. It is designed to help the user secure total privacy for communications or recorded memos. Just as its scrambling, technically called “speech inversion”, can be decoded by knowledgeable users of similar equipment, the SS70A in turn can be used experimentally to descramble some public service communications, cordless phones and other systems where low cost scrambling is employed. Similar to the regulations affecting the use of mobile VHF scanners, it is the responsibility of the user of this equipment to know and observe any applicable laws regarding the interception and descrambling of transmissions employing speech inversion. “Speech inversion” is a process that interchanges high and low speech frequencies by removing the carrier frequency and transmission of only one sideband in a communications link. This renders the speech unintelligible unless received by a device capable of replacing the carrier frequency exactly. The single inversion scrambling technique used in the SS70A is adequate to minimize casual eavesdropping or ambulance chasing. Greater security is possible, using precision audio filters, and by inverting more than one audio range simultaneously. SS70A CIRCUIT DESCRIPTION Radio amateurs will notice some similarity between the SS70A and a basic sideband transmitter. However, in the speech scrambler’s case, the audio input is mixed with a local oscillator running right in the audio range (3.3 KHz) rather than an RF oscillator, and it is precisely that modulation of such a low frequency that results in speech inversion. Let’s look more closely at what happens in the circuit. Have a glance at your schematic and follow along. At the heart of the speech scrambler circuitry is the MX128 full-duplex frequency inversion scrambler IC. This chip contains a balanced modulator and several digital audio filters for both transmit and receive audio paths. In addition, the 3.3 KHz injection frequency is generated within the MX128. J3 provides selection o...