SU56141A1 - Direct Frequency Tube Generator - Google Patents

Description

In measurement technology, it is often necessary to use a variable frequency tube generator with a wide and continuous frequency range. In this case, the frequency change is made by changing the coils and capacitors, and the frequency setting is made according to tables or graphs. In the proposed generator circuit, the readout is performed directly on the instrument scales and the essence of the invention is as follows.

FIG. 1 of the drawing is a schematic diagram of an oscillating circuit of such a generator. Suppose that a change in the capacitance of a smoothly variable capacitor C ,, from the value C ;, to O causes a change in frequency from the value of / to f. By changing the values of Cn, and C ,,, it is easy to achieve that the same change in capacitance Cn causes a change in frequency from / + - to / 2A. In a similar way, one can find such values С, „and С„ for which the variable capacitor C., will change the frequency from / 1 | 2D to / -f and so on. Thus, if we switch the capacitor t С,., And С „simultaneously, by means of a switch P with a number of positions equal to n, we can continuously change the frequency in the range from / to / + pl. The scale of the variable capacitor must be graduated in frequency from O to Au to determine the frequency of the generator necessary to the frequency counted on the scale of the variable capacitor C.,. add the value / + (l - /) Agde n - the position of the switch. ; To further extend the range, replace the coil with an LI coil.

; / f l-i

; Lo: -T - 1. In this case, the same koi, -

; Capacitor C., will change the frequency z; nerator in the first position of the switch P from the value of / -; wA; u ,,

+ „..,.

/ Naturally, the attitude

 is chosen to be a prime number: (for example, 2). In the second position; switch capacitor C changes em

,, . / "BUT ,

frequency from / - / gA - ----- l to