CRYSTAL SWITCH A2000 - TM-11-5820-401-34-30022

TM 11-5820-401-34-3/0967-LP-432-3060

1-17.

CRS SECOND MIXER A3300 AND CRYSTAL SWITCH A2000. (CONT)

CRYSTAL SWITCH A2000

The A2000 assembly contains two crystal controlled oscillators: the interpolation oscillator and the

reference oscillator. The reference oscillator is discussed in paragraph 1-15.

The interpolation oscillator's output frequency is controlled by one of ten possible crystals which are

selected by a switch through the action of the radio's gear train. Each crystal corresponds to two

positions of the radio's KC control, out of the 20 possible 50-kHz increments that can be selected

between whole-numbered frequencies. For example, in tuning from 30 to 31 MHz, the KC control

selects frequencies of 30.05, 30.10, 30.15, 30.20, 30.25, etc. The first two steps (ie, 30.05 and

30. 10) correspond to a particular crystal in the crystal switch. The next two steps (ie, 30.15 and

30.20) have a different corresponding crystal. This pattern repeats itself until all ten crystals have

been individually selected. When the MC-TUNE-KC control reaches 31.00 MHz, the same crystal is

selected as was used for 30.00 MHz.

The following table lists the ten pairs of radio dial frequencies between each whole-number setting,

the number of the corresponding crystal, and the interpolation oscillator's frequency when that

particular crystal is selected.

CRYSTAL

RADIO DIAL KC

OSCILLATOR

NUMBER

FREQUENCY

Y2007

46.950 MHz

.05 or .10

.15 or .20

Y2008

47.050 MHz

Y2009

.25 or .30

47.150 MHz

Y2010

47.250 MHz

.35 or .40

.45 or .50

Y2005

47.350 MHz

Y2004

47.450 MHz

55 or .60

Y2003

47.550 MHz

,55 or .70

.75 or .80

Y2002

47.650 MHz

Y2001

.85 or .90

47.750 MHz

Y2006

.95 or .00

46.850 MHz

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