| 摘要 |
<p>1,261,386. Oscillators; frequency modulation. HASLER A.G. 9 July, 1969 [11 July, 1968], No. 34693/69. Headings H3F and H3R. A phase shift sine wave oscillator has an amplifier V whose output is connected to its input through a network as shown wherein F, G are capacitors (or resistors) and Q<SP>1</SP>, S<SP>1</SP>, T<SP>1</SP> are resistors (or capacitors), the element P being either a switch or a resistor or a capacitor. If the amplifier V instead of being a voltage amplifier is a current amplifier, its input and output connections to the network are reversed. The output frequency is varied, without changing the voltage dividing ratio at E and therefore without affecting the output amplitude, by any of the following methods: (a) by opening or closing a switch constituting the element P to give two different frequencies whose ratio depends on a given relationship between F, G, Q<SP>1</SP>, S<SP>1</SP>, and T<SP>1</SP>; (b) by varying a resistance (or capacitance) constituting the element P to give a range of frequencies between the two frequencies in (a); or (c) varying a resistance (or capacitance) constituting the impedance T<SP>1</SP> provided that the capacitors (or resistors) F, G are equal and that P<SP>2</SP> = Q<SP>1</SP>. S<SP>1</SP>. In these arrangements, the element P is of the same impedance type (i.e. resistor or capacitor) as Q<SP>1</SP>, S<SP>1</SP> and T<SP>1</SP>. If the amplifier is a differential amplifier, its second input is fed from the junction of two resistors connected from the output to earth.</p> |
