Ramsey Electronics MR6 用户手册

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页码 16
MR6 
• 4  
INTRODUCTION  
 
Welcome to the latest innovation in electronics technology using (S)urface 
(M)ount (T)echnology, or SMT. Just as when the transistor revolutionized the 
amount of  space required to construct electronic circuits, the advent of  
surface mount components have further “shrunk” the dimensions of what we 
are accustomed to seeing in modern day circuits. These “chip” components 
are commonly used in today’s miniature circuits including everything from 
camcorders  to high speed computers. We wanted to design a kit that 
accentuated their small size, so what better than a micro FM transmitter! 
Many low cost wireless transmitters are susceptable to frequency drift when 
held in the hand, placed on a metal table or subject to close proximity of a 
body. This kit uses crystal control to reduce any possibiliy of frequency drift.  
 
While this kit and manual were designed with the beginner in mind, it should 
also be stated that this kit qualifies as a “Skill Level 2” due to the nature of 
the assembly using surface mount components. While this isn’t intended to 
“scare you off” it is not recommended that this be your first electronics 
assembly project. While we have included extra SMT components in case 
you lose or damage a “chip” component, care should still be taken to 
assemble the kit with the utmost care - an uncontrolled sneeze could blow 
your kit away! 
 
While the components may seem strange looking at first (where are the 
leads??!!) rest assured that they are not too difficult to install. A friendly 
warning, however, don’t pull out your trusty soldering gun for this project (our 
repair techs have a pet statement, “do you know what the soldering gun’s 
light is for - it’s to see what you’re burning up!”) as the gun generates too 
much heat for the tiny solder “tabs” on the component ends. A small pair of 
tweezers and good eye to hand coordination are also necessary for proper 
assembly of this kit. A magnifying lens is recommended to check solder 
connections. 
 
MR6 CIRCUIT DESCRIPTION 
 
The MR6 is a three stage crystal controlled transmitter consisting of a crystal 
oscillator followed by two frequency multipliers. The crystal oscillator 
operates at 12, 16 or 24 MHz, depending upon crystal used. The first 
frequency multiplier is tuned to the fourth, third or second harmonic of the 
crystal oscillator, producing a stong output at 1/3 of the final 146 MHz output 
frequency. The second frequency multiplier operates as a frequency tripler, 
producing the desired 146 MHz output frequency. Broadband coupling is 
used to allow the user to select different crystals for various output 
frequencies.