JPH0520431U - Oscillator - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide an oscillator which can easily cope with various frequency signals. According to the present invention, an oscillating circuit whose oscillating frequency changes according to a control signal, a harmonic generating circuit for generating a reference harmonic signal with respect to the output of the oscillating circuit, the oscillating circuit and the harmonic A mixing circuit for mixing the outputs of the generating circuit,
A frequency divider that divides the output of the mixing circuit, a phase comparator that compares the phase of the output signal of the frequency divider with a reference frequency signal, and a phase difference obtained by the phase comparator of the oscillator circuit. And a control signal generating means for converting into a control signal.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention particularly relates to an oscillator that can be used in broadcasting equipment.

[0002]

[Prior Art]

 As is well known, broadcasting equipment uses a wide variety of standard frequency signals depending on the broadcasting system, frequency band used, etc. In the past, corresponding oscillators were used, and the types of oscillators also varied. For this reason, maintenance and replacement of the oscillator are very expensive.

[0003]

[Problems to be solved by the device]

 As described above, the conventional oscillator cannot easily cope with various frequency signals. The present invention has been made to solve the above problems, and an object thereof is to provide an oscillator that can easily cope with various frequency signals.

[0004]

[Means for Solving the Problems]

 In order to achieve the above object, an oscillator according to the present invention comprises an oscillation circuit whose oscillation frequency changes according to a control signal, and a harmonic generation circuit which generates a reference harmonic signal with respect to the output of this oscillation circuit. , A mixing circuit that mixes each output of the oscillation circuit and the harmonic generation circuit, a divider that divides the output of this mixing circuit, and a phase comparison between the output signal of this divider and the reference frequency signal. And a control signal generating means for converting the phase difference obtained by the phase comparator into a control signal for the oscillation circuit.

[0005]

[Action]

 In the oscillator with the above configuration, the mixing circuit is inserted in the automatic phase control loop, and the comparison signal frequency is generated by the harmonic generation circuit.Therefore, the mixing down can be performed within a certain width regardless of the output frequency of the oscillation circuit. it can.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows the configuration thereof, and f1 is a reference signal such as a synchronizing signal. The reference signal f1 is supplied to the first and second frequency dividers 11 and 12. The first frequency divider 11 divides the reference signal f1 to generate a reference frequency signal f6 of the phase comparator 17, which will be described later. The second frequency divider 12 divides the reference signal f1 to generate the fundamental wave frequency signal f8 of the harmonic generation circuit 13.

The harmonic generation circuit 13 generates a frequency signal f3 that is a positive multiple of the fundamental wave frequency f8, and the generated harmonic signal f3 is supplied to the mixing circuit 14. The mixing circuit 14 inputs a frequency signal f2 from a VCO (voltage controlled oscillator) 19 described later, mixes a harmonic signal f3 with the frequency signal f2 to generate a mixed signal f4. f4 is supplied to the LPF (low pass filter) 15.

The LPF 15 mixes down the mixed signal f 4 to extract a comparison signal f 5 having a certain frequency, and the comparison signal f 5 is supplied to the third frequency divider 16. The third frequency divider 16 divides the comparison signal f5 to generate a comparison frequency signal f7, and the comparison frequency signal f7 is supplied to the phase comparator 17. The phase comparator 17 compares the comparison frequency signal f7 with the reference frequency signal f6 to generate a phase difference signal f9 between them, and the phase difference signal f9 is supplied to the loop filter 18.

The loop filter 18 converts the input phase difference signal f9 into a voltage signal VC, and this voltage signal VC is supplied to the VCO 19 as a frequency control signal. The VCO 19 variably controls the oscillation frequency according to the input control signal VC, and the frequency signal generated here is supplied to the target device as the output signal f2.

That is, in the oscillator having the above configuration, the mixing circuit 14 and the harmonic generation circuit 13 are provided in a normal automatic phase control loop (PLL), and the fundamental frequency signal f8 generated by the harmonic generation circuit 13 is generated. The harmonic frequency signal f3 that is a positive multiple of x is mixed with the output frequency signal f2 generated by the VCO 19, and the comparison frequency signal f7 is generated based on this mixed signal f4, so that it is constant regardless of the output frequency f2 of the oscillator circuit. You can mix down to the width.

Therefore, the oscillator configured as described above can easily cope with various frequency signals, and, for example, can sufficiently meet various demands of frequency signals of broadcasting equipment. Needless to say, various modifications can be made in the same manner without departing from the scope of the invention.

[0013]

[Effect of the device]

 As described above, according to this invention, it is possible to provide an oscillator that can easily cope with various frequency signals.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a configuration of an embodiment of an oscillator according to the invention.

[Explanation of symbols]

11, 12, 16 ... Divider, 13 ... Harmonic generation circuit, 1
4 ... Mixing circuit, 15 ... Low pass filter, 17 ... Phase comparator, 18 ... Loop filter, 19 ... Voltage controlled oscillator.

Claims (1)

[Scope of utility model registration request] 1. An oscillation circuit whose oscillation frequency changes according to a control signal, a harmonic generation circuit which generates a reference harmonic signal with respect to the output of the oscillation circuit, and an output of the oscillation circuit and harmonics. A mixing circuit for mixing the outputs of the generating circuit, a frequency divider for dividing the output of the mixing circuit, a phase comparator for phase-comparing the output signal of the frequency divider and the reference frequency signal, and this phase comparator. An oscillator comprising a control signal generating means for converting the phase difference obtained in step 1 into a control signal for the oscillation circuit.