SU932620A1 - Frequency synthesizer - Google Patents

Description

I

j The invention relates to devices for generating electrical oscillations and can be used in radio receiving and radio transmitting devices for frequency control.

A frequency synthesizer is known, which contains a controllable oscillator, a counter, a comparator unit, a digital-to-analog converter, a controlled switch, an integrator and an adder, and a time interval shaping unit whose output is connected to another counter of the counter, a memory block whose input is connected. with the output of the counter, and the output with another input of the comparator unit, and the converter of the angle of rotation of the manual adjustment element to the voltage, the analog output of which is connected to another input of the adder, and the logical the output is connected to the control input of the controllable switch, and to the input of the memory block f 1

However, in the known frequency synthesizer, the frequency tuning is performed by repeatedly turning the tuning knob of the transducer of the angle of rotation of the manual tuning-to-voltage element, which leads to a low tuning speed when changing from one frequency value to another.

The purpose of the invention is to increase the tuning rate over the frequency range.

To do this, in a frequency synthesizer containing a controllable oscillator, a counter, a comparison unit, a digital-analog converter, a control switch, an integrator and an adder, and a time interval shaping unit whose output is connected to another counter input, the memory block, the input which is connected to the output of the counter and the output to another input of the comparison unit, and a converter of the angle of rotation of the tuning voltage to voltage element, the analog output of which is connected to another input of the adder and the logical xit is coupled to a control input of the controllable switch and to the input of the memory unit, between the analog output rotational angle transducer element manual adjustment in voltage and the input manual adjustment signal controlled switch unit is entered nonlinear elements. FIG. Figure 1 shows a structural electrical circuit offering a multi-frequency synthesizer; in fig. 2 - the characteristic Ug, j, t (Upu) of the block of nonlinear elements; in fig. 3 - control knob for controllable switch and frequency control sectors (conditionally). The frequency synthesizer contains a ringed controlled oscillator 1, a counter 2, a comparison block 3. digital-to-analog converter (UAn k, control switch 5, integrator 6 and adder 7, as well as block 8 for forming time intervals, memory block 9, converter 10 for turning the element of manual tuning into voltage and block 11 for non-linear elements. Block non-linear elements have a transient characteristic described by an odd function whose value is zero in the interval 0 / Ugx / / UnopA where and then is the threshold voltage, and the characteristic may increase as / Tt3p / r® as shown in FIG. 2. The Converter 10 angle n The ovary of the manual tuning element in the voltage can be performed, for example, in the form of a potential with a manual adjustment. The frequency synthesizer works as follows .. I As long as the operator’s hand does not touch the potentiometer knob of the converter 10, the signal at the control input of the controlled switch 5 is zero therefore, the automatic frequency stabilization ring works. The frequency of the controlled oscillator 1, measured by counter 2, is compared with the frequency recorded in memory block 3, equal to the frequency of the controlled oscillator in End of manual overhaul. The code spacing of 9 04 these frequencies, which occurs when the frequency of the controlled oscillator 1 is changed, is converted to analog form in the ILP. The received signal is integrated and through the adder 7 is fed to the control input of the controlled oscillator 1, and the frequency of this oscillator changes in the direction of reducing the initial error of the controlled oscillator frequency and the frequency recorded in memory block 3. As a result, the frequency of the controlled oscillator is kept constant for an arbitrarily large interval in c)). When manually adjusting the angle converter 10 of the manual tuning element to the voltage, the voltage appears at the control input of the controlled switch 5, the automatic frequency control ring is broken. In this case, the frequency of the controlled oscillator 1 is controlled by the output voltage of the adder 7, equal to the sum of the voltages coming from the converter 10 and from the integrator 6 (UHHT). The integration voltage Ujj varies in proportion to the input voltage, equal to the output voltage of the block of nonlinear elements and the time of its existence at the input (U is the initial voltage on the integrator). Therefore, if the potentiometer is in the position corresponding to the dead zone of the block of nonlinear elements, i.e. if the potentiometer adjustment knob is turned within ± sat (Fig. 3), then. Outside this zone (when turning the knob by an angle ranging from oi to p) Ug) will increase as the angle of rotation increases. The total working sector of the knob's rotation can be no more, and the sectors of the rotation corresponding to the smooth frequency adjustment and the sectors of the rotation corresponding to the overview frequency tuning and the tuning speed can be chosen arbitrarily by adjusting the unit elements to ensure maximum energy efficiency of the manual tuning process. . Thus, a smooth adjustment is made when the potentiometer is rotated within the dead zone of a block of nonlinear elements, when nor o- If necessary, moving from one tuning range to another by rotating the potentiometer through a corresponding angle, the nonlinear elements of block 11 are out of the dead zone. As a result, the frequency is tuned (and it can be done at any desired speed, and the potentiometer remains in a fixed position. When approaching the required tuning frequency value, the potentiometer is returned to the position corresponding to the dead band of the nonlinear elements of the unit, and smooth tuning, i.e., smooth tuning with the same density as in a known synthesizer, to any frequency of the range.

However, the transition from one frequency value to another in the proposed frequency synthesizer is carried out at a faster speed than at a known and at a lower, in comparison with a known synthesizer, angle of rotation of the potentiometer knob, since the tuning from one frequency value to another is not due to repeated turning the potentiometer knob, as in the well-known synthesizer, where Uy |, p Uf, (Up, and due to an increase in voltage at the integrator output, where and p + and. When the control voltage changes, the frequency of the controlled generator changes , which is measured by counter 2 and recorded in memory block 3, i.e. after manual tuning is completed, the last value of the current frequency is stored in the memory block, which is stored until the next manual tuning.

Thus, the proposed frequency synthesizer makes it possible to increase the tuning rate over a range of frequencies, improve the usability, and improve the consumer properties of the synthesizer.

Claims (1)

1. JHEE Transactions, Vol. CE-23, 1977, p. t kG-ki46.