switch positions.

Read sampling frequency on the counter.

Divide the

sampling frequency into the estimated frequency to obtain N.

Turn

thumbwheels to the value determined for N. Read the actual input frequency

on the counter's display.

When the input frequency is known to be outside the limits for direct

calculation of N, a different procedure is followed.

The thumbwheels are

set to 001, Frequency MHz is tuned to zero beat or phase lock while

observing Level Adj and Mode switch positions.

The counter readout is

recorded as f1. Frequency MHz is returned to an adjacent zero beat or phase

lock and the counter readout is recorded as f2.

The first frequency f1

divided by the difference in the frequencies yields harmonic number N of the

second frequency f2.

EXAMPLE 1.

Assume unknown fx is approximately 11.9 GHz; Time Base = 1 ms.

a. Where f2 is lower than f1:

fx = (N - 1) f1 and fx = Nf2,

N = f1/(f1 - f2).

f1 = 119532.

kHz (read on counter) tuning lower in frequency gives

f2 = 118349.

kHz (read on counter)

f1 - f2 = 1183.

kHz

N = 119.5/1.183 = 101, set thumbwheels to 101,

fx = 101 x 118.349 = 11953261.

kHz (read on counter).

b. Where f2 is higher than f1:

fx = (N + 1) f1 and fx = Nf2,

N = f1/(f2 - f1).

f1 = 119532.

kHz (read on counter) tuning higher in frequency gives

f2 = 120740.

kHz (read on counter)

f2 - f1 = 1208.

kHz

N = 119.5/1.208 = 99, set thumbwheels to 99, fx = 120.740 x 99 =

11953261. kHz (read on counter).