Patent GB-1370019-A (GB)
Title: Microwave frequency sweep generator
IPC: H03B23/00
Filed: 1971-12-30
Abstract: 1370019 Frequency sweep generators NARDA MICROWAVE CORP 30 Dec 1971 [4 Jan 1971(2)] 60649/71 Heading H3R A microwave frequency sweep generator using oscillating means 500, Fig. 5, to sweep an initial frequency band and multiplier means 520 to select harmonics of the frequencies in the initial band to sweep a higher frequency band has means for tuning the oscillating means and multiplier means in response to direct current voltage levels discretely indicative of a frequency desired, means 10-13 for establishing a plurality of voltage levels, first means for selecting one of the voltage levels for tuning the generator to a single frequency, second means for selecting one of the voltage levels for tuning the generator to sweep a frequency band #F centered on the selected frequency F and means for selecting two of the voltage levels for tuning the generator to sweep a frequency band between the frequencies selected. The voltage levels are selected by voltage divider networks (Fig. 9, not shown) associated with each digital frequency selector F1, M1, M2 and F2 which has thumb wheels 17-19, 21 controlling a voltage divider network and a digital display 14-16, 20. Digital frequency selector F1 sets the start frequency when operating in the Start/Stop mode, the centre frequency when operating in the #F mode or the operating frequency when operating in the CW mode as selected by buttons 23, 24 or 25. Digital frequency selector M1 sets the start or stop frequency when operating in the Start/Stop mode, the centre frequency or one of the marker frequencies when operating in the #F mode, or the operating frequency when operating in the CW mode. The digital frequency selector M2 functions in the same manner as M1 for a second marker frequency. Digital frequency selector F2 functions the same as F1 except that it displays the stop frequency when operating in the Start/Stop mode. The digital frequency selectors F1, M1, M2 or F2 are selected by buttons 26-29 and the direction of sweep may be up or down. The generator may operate in response to external frequency control by operating button 22. The time required to sweep a band is selected by lever 33 which selects four sweep ranges of a Miller integrator (Fig. 8, not shown). The generator may be synchronized internally, to the line, or externally by lever 53. Modulation may be selected by lever 39 to provide external FM or AM or internal square wave or no modulation. Details of the generator system are described (Figs. 2-4, not shown). The output from a YIG tuned sweep oscillator 500 (Fig. 5) is coupled directly to the output of a combiner 521 or via a YIG tuned step recovery diode multiplier 520 to the output as controlled by a switching circuit Q530. Circuits, including integrated circuits, providing harmonic switching voltages to the multiplier and tracking between the sweep oscillator and the harmonic multiplier (Figs. 6 and 7, not shown) are described. Gating circuits (Figs. 10A and 10B, not shown) are described which prevent simultaneous selection of the functions selccted by the buttons 22-25 or prevent three selections of frequency by the buttons 26-29 when in the Stop/Start mode or prevent simultaneous selection of the frequencies selected by buttons 26-29 when in the #F or CW modes.