FUNCTIONAL DESCRIPTION 



General 



The PFR-193 is a small, self-contained precision electromechanical 

 recorder, which generates precise solid state keying pulses for the com- 

 panion sonar transceiver, and prints the return echoes with a timing 

 stability of 2 ppm over the operating temperature range. The recording 

 medium used is dry electrosensitive paper, which provides high resolution 

 and excellent white-to -black contrast on a good dimensionally-stable base. 



The recorder consists of a mechanical assembly unit and an electrical 

 assembly unit, (Fig 1), both housed in a rugged cabinet. The mechanical 

 unit sweeps the styli across the paper at a uniform linear rate while ad- 

 vancing the paper under the styli from a paper feed to a take-up system. 

 The mechanism also generates, through the timing pulse generator, highly 

 accurate and stable timing pulses to initiate actions of keying, gating, 

 and calibration marking. 



The electrical assembly, responsible for control and power generation 

 functions, features a highly stable power source of 2 ppm which supplies 

 power to the synchronous motor in the mechanical unit. In addition, it 

 processes the timing signals from the mechanical unit and translates 

 these into key-pulse, gate, and calibration marking signals. The print 

 amplifier processes the sonar receiver output information, which, in the 

 end product, provides the operator with recordings of excellent quality 

 and highest resolution. 



Sweeping 



The components of the sweeping function (Fig 2) are responsible 

 for the transformation of a precision frequency into a smooth jitter- 

 free linear motion of the styli across the paper. A 60-cps oscillator, 

 with a frequency stability of +2 ppm over the recorder operating temper- 

 ature range, and a stability of +1 ppm over any 10° C range, pro"vides a 

 square wave output to the DC-to-AC inverter. The inverter is a high 

 efficiency source of 110-V AC power to the synchronous motor that in turn 

 generates the stylus motion. In addition, 5 watts of precision AC is 

 available at a rear-mounted receptacle, so that a wall clock or other 

 timing device may be driven by the recorder. Through an auxiliary con- 

 nection, the recorder can be driven by an external 60-cps source, to 

 check its accuracy with WW, or to play back tapes of soundings. The 

 DC-to-AC inverter is fed from a regulated DC voltage supply, thus assuring 

 voltage regulation at the synchronous motor. This U-pole l800-rpm motor 

 has been designed to run precisely at synchronous speed, while maintain- 

 ing high damping and extremely little jitter. The motor shaft is 

 connected to a precision gear train, containing three electromagnetic 

 clutches, Energizing the proper clutch selects the gear ratio corres- 

 ponding to the scale in use. The syflc pulley is attached to the output 



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