Agilent 1958-11 free download

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HEWLETT-PACKARD JOURNAL T E C H N I C A L I N F O R M A T I O N F R O M T H E - h p - L A B O R A T O R I E S Vol. 10 No. 3-4 PUBLISHED BY THE HEWLETT-PACKARD COMPANY, 275 PAGE MILL ROAD, PALO ALTO, CALIFORNIA NOV. -DEC., 1958 5 x 10'VWeek Time Base Accuracy in the 10 MC Frequency Counter REFINEMENT of techniques in several for example, that a measurement of a 100- fields is currently generating a need for megacycle frequency (using the counter with making routine frequency measurements to in its heterodyne converter) will be accurate with creased degrees of accuracy. A good example in ± 5 cycles in the week following calibration of this need lies in the single-sideband field or ±10 cycles in the second week, ± short-term where it has become desirable to be able to stability in each case. make fast, convenient meas Actually, the performance of the oscillators urements of VHP frequencies has been well above ratings, and the ratings are to within a matter of cycles in considered to be subject to later improvement. checking transmitter carriers, receiver oscilla Short-term stability, for example, is rated as tors, filter response, etc. within ±3 parts in 108, but typical short-term For such work the -hp- 10-megacycle fre performance is considerably better, as shown in quency counter is now available with a new Fig. 2. Note that one major vertical division in time base crystal oscillator of very high per Fig. 2 is equal to 1 part in 108 so that the sta formance. The new time base is rated as having bility can typically be described in parts in 109. a long-term stability of within ±5 parts in 108 It is of interest to recall that this performance, per week. This tolerance is directly transfer while within about one order of magnitude of able to frequenc