CN215378963U

CN215378963U - Hybrid modulation oscillating circuit

Info

Publication number: CN215378963U
Application number: CN202121494157.6U
Authority: CN
Inventors: 苏雪彪; 苏雪峰
Original assignee: Shenzhen Go On Electronics Co ltd
Current assignee: Shenzhen Go On Electronics Co ltd
Priority date: 2021-07-01
Filing date: 2021-07-01
Publication date: 2021-12-31
Anticipated expiration: 2031-07-01

Abstract

The utility model provides a hybrid modulation oscillation circuit, and belongs to the field of wireless transmitting equipment circuits. The frequency control circuit comprises a frequency control module, a first frequency oscillation circuit and a mixing circuit, wherein the output end of the frequency control module is connected with the first frequency oscillation circuit and used for controlling oscillation signals of the first frequency oscillation circuit, and the mixing circuit is respectively connected with the output end of the first frequency oscillation circuit and IF intermediate frequency signals and used for mixing the oscillation signals output by the first frequency oscillation circuit with the IF intermediate frequency signals and modulating the IF intermediate frequency signals to required frequency. The utility model has the beneficial effects that: the signal can be modulated into a frequency band with lower application rate, so that the interference is low, the noise is low, and the signal quality is effectively improved.

Description

Hybrid modulation oscillating circuit

Technical Field

The utility model relates to a wireless transmitting equipment circuit, in particular to a hybrid modulation oscillating circuit.

Background

The FM stereo transmitter is used for transmitting stereo signals in an FM frequency modulation manner, but the frequency band used by the FM frequency modulation transmitter overlaps with the frequency bands of devices such as mobile phones, and the utilization rate is very high, so that the FM stereo transmitter is easily interfered by other devices, and therefore the problems of high noise, poor tone quality and the like of received stereo signals are caused, and the user experience is not good.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems in the prior art, the utility model provides a hybrid modulation oscillation circuit which modulates an FM modulation signal into a specific frequency, thereby avoiding the interference of the same frequency band devices such as a mobile phone and the like.

The frequency control circuit comprises a frequency control module, a first frequency oscillation circuit and a mixing circuit, wherein the output end of the frequency control module is connected with the first frequency oscillation circuit and used for controlling oscillation signals of the first frequency oscillation circuit, and the mixing circuit is respectively connected with the output end of the first frequency oscillation circuit and IF intermediate frequency signals and used for mixing the oscillation signals output by the first frequency oscillation circuit with the IF intermediate frequency signals and modulating the IF intermediate frequency signals to required frequency.

The utility model is further improved and also comprises a filtering and amplifying circuit, wherein the input end of the filtering and amplifying circuit is connected with the output end of the mixing circuit, and the output end of the filtering and amplifying circuit is connected with a power amplifying circuit at the later stage.

The utility model is further improved, the filtering amplifying circuit comprises a first filtering unit, a first amplifying unit and a second amplifying unit, wherein the first filtering unit, the first amplifying unit and the second amplifying unit are sequentially arranged according to the signal flow direction.

The utility model is further improved, and the device also comprises a second filtering unit, wherein the second filtering unit is arranged between the first amplifying unit and the second amplifying unit.

The utility model is further improved, the first filtering unit and the second filtering unit are both filters, and the first amplifying unit and the second amplifying unit are both triode circuits.

The utility model is further improved, and the frequency control module comprises a singlechip circuit for generating crystal oscillator frequency and a phase-locked loop control circuit for locking the output crystal oscillator frequency.

The utility model is further improved, the first frequency oscillation circuit comprises a triode T12, the base electrode of the triode T12 is connected with the output end of the phase-locked loop control circuit through an inductor, a capacitor and a diode VD2 which are connected in series, the anode of the diode VD2 is connected with the base electrode of the triode T12, the emitter electrode of the triode is grounded through an inductor L22 and a resistor R41 which are connected in series, and the collector electrode of the triode T12 is respectively connected with a power supply and outputs oscillation signals.

In a further improvement of the present invention, a feedback terminal FIN is further led out from the output terminal of the triode T12, and the feedback terminal is connected to the feedback input terminal of the phase-locked loop control circuit.

The utility model is further improved, the frequency mixing circuit comprises a local oscillator amplification and isolation unit and a frequency division unit, the frequency division unit is respectively connected with the output end of the local oscillator amplification and isolation unit and the output end of the IF intermediate frequency signal, and the frequency division unit is used for mixing and modulating two paths of signals and outputting a set frequency signal.

The utility model is further improved, the isolation amplifying unit comprises a triode T21 and peripheral devices thereof, the base electrode of the triode T21 is respectively connected with the output end of the first frequency oscillation circuit and one end of a resistor R38, the resistor R38 is connected with an inductor L26 and a resistor R64 in series and then connected with a power supply, the emitter electrode of the triode T21 is grounded, and the collector electrode is respectively connected between the input end of the frequency dividing unit and the inductors L26 and R38.

Compared with the prior art, the utility model has the beneficial effects that: the FM stereo signal modulator can modulate signals into a frequency band with low application rate, so that the interference is low, the noise is low, the signal quality is effectively improved, the original FM stereo signal with intermediate frequency is modulated into an ultrahigh frequency signal, the signal transmission efficiency is greatly improved, and the loss in the transmission process is low.

Drawings

FIG. 1 is a block diagram of the present invention;

fig. 2-6 are schematic circuit diagrams of an embodiment of the present invention, wherein fig. 2 is a schematic circuit diagram of a single chip microcomputer; fig. 3 is a schematic diagram of a phase-locked loop control circuit, fig. 4 is a schematic diagram of a UHF oscillator circuit, fig. 5 is a schematic diagram of a mixer circuit, and fig. 6 is a schematic diagram of a filter amplifier circuit.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

As shown in fig. 1, the present invention includes a frequency control module, a first frequency oscillating circuit, and a mixing circuit, wherein an output terminal of the frequency control module is connected to the first frequency oscillating circuit for controlling an oscillating signal of the first frequency oscillating circuit, and the mixing circuit is respectively connected to an output terminal of the first frequency oscillating circuit and an IF intermediate frequency signal for mixing the oscillating signal output by the first frequency oscillating circuit with the IF intermediate frequency signal and modulating the IF intermediate frequency signal to a desired frequency.

The frequency control module comprises a singlechip circuit for generating crystal oscillator frequency and a phase-locked loop control circuit for locking the output crystal oscillator frequency. The frequency control module comprises a singlechip circuit for generating crystal oscillator frequency and a phase-locked loop control circuit for locking the output crystal oscillator frequency. The rear stage of the frequency mixing circuit also comprises a filtering and amplifying circuit, the input end of the filtering and amplifying circuit is connected with the output end of the frequency mixing circuit, and the output end of the filtering and amplifying circuit is connected with the power amplifying circuit of the rear stage.

As an embodiment of the utility model, the FM stereo signal or the FM audio signal is modulated into Ultra High Frequency (UHF) for transmission, the UHF frequency of the embodiment adopts 600-1000MHz, and users in the UHF frequency range are very few, so that the modulated audio signal has small interference, the noise caused by the interference is reduced, and the signal quality is greatly improved. In addition, the original FM stereo signal of the intermediate frequency is modulated into the ultrahigh frequency signal, so that the signal transmission efficiency is greatly improved, and the loss in the transmission process is reduced. Of course, the present example can also modulate the FM audio signal into other, less common frequency bands.

As shown in fig. 2, the mcu of this embodiment includes an mcu IC6 and a crystal oscillator Y2 connected to the mcu IC6 for generating a stable oscillation frequency, which is output via the pin 15.

As shown in fig. 3, the PLL control circuit of this embodiment includes a control IC5, wherein a pin 11 of the control IC is connected to a pin 15 of a single chip IC6 to serve as an external input reference signal. Then, the frequency and phase of the oscillation signal inside the loop are controlled by using the external input reference signal, and the oscillation signal is output to the UHF oscillation circuit through pin 3 of the control IC5, and the feedback signal of the UHF oscillation circuit is received through pin 1.

As shown in fig. 4, the UHF oscillator circuit of this example includes a transistor T12, the base of the transistor T12 is connected to the output end of the pll control circuit through an inductor, a capacitor and a diode VD2 connected in series, the anode of the diode VD2 is connected to the base of the transistor T12, the emitter of the transistor is grounded through an inductor L22 and a resistor R41 connected in series, and the collector of the transistor T12 is connected to the power supply and outputs an oscillating signal, respectively. The output end of the triode T12 is also led out of a feedback end FIN through a resistor and a capacitor which are connected in series, and the feedback end is connected with a feedback input pin 1 of a control IC5 of the phase-locked loop control circuit.

As shown in fig. 5, the mixer circuit of this embodiment includes a local oscillator amplification and isolation unit and a frequency division unit, where the frequency division unit is respectively connected to an output end of the local oscillator amplification and isolation unit and an output end of the IF intermediate frequency signal, and the frequency division unit is configured to mix and modulate two paths of signals and output a set ultrahigh frequency signal.

As an embodiment of the present invention, the isolation amplifying unit in this embodiment includes a transistor T21 and its peripheral devices, a base of the transistor T21 is connected to an output terminal of the first frequency oscillating circuit and one end of a resistor R38, respectively, the resistor R38 is connected to a power supply after being connected in series with an inductor L26 and a resistor R64, an emitter of the transistor T21 is grounded, and a collector is connected between an input terminal of the frequency dividing unit and the inductor L26 and the resistor R38, respectively.

After the two paths of signals are mixed, a plurality of frequencies can be generated in the signals, so that the required frequencies can be effectively separated through the frequency divider and then sent to a rear-stage RF filtering and amplifying circuit, and RF is the meaning of radio frequency signals.

As shown in fig. 6, the filter amplifier circuit of this example includes a first filter unit, a first amplifier unit, a second filter unit, and a second amplifier unit that drive the subsequent power amplifier circuit, which are sequentially arranged in the signal flow direction.

The first filtering unit and the second filtering unit are both filters, and the first amplifying unit and the second amplifying unit are both triode circuits. Two-stage filtering makes the signal frequency after handling more accurate, and the radio frequency signal after the first order filtration passes through the first amplification unit and enlargies the back, can be discerned and filter by the second filter unit more easily, the second amplification unit is the driving tube for promote the power amplifier circuit of back-end, then with radio frequency signal through antenna transmission.

The above-described embodiments are intended to be illustrative, and not restrictive, of the utility model, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A hybrid modulation oscillator circuit, characterized by: the frequency control circuit comprises a frequency control module, a first frequency oscillation circuit and a mixing circuit, wherein the output end of the frequency control module is connected with the first frequency oscillation circuit and used for controlling oscillation signals of the first frequency oscillation circuit, and the mixing circuit is respectively connected with the output end of the first frequency oscillation circuit and IF intermediate frequency signals and used for mixing the oscillation signals output by the first frequency oscillation circuit with the IF intermediate frequency signals and modulating the IF intermediate frequency signals to required frequencies.

2. The hybrid modulated oscillator circuit of claim 1, wherein: the input end of the filtering amplifying circuit is connected with the output end of the mixing circuit, and the output end of the filtering amplifying circuit is connected with a rear-stage power amplifying circuit.

3. The hybrid modulated oscillator circuit of claim 2, wherein: the filtering amplification circuit comprises a first filtering unit, a first amplification unit and a second amplification unit, wherein the first filtering unit, the first amplification unit and the second amplification unit are sequentially arranged according to the signal flow direction.

4. The hybrid modulated oscillator circuit of claim 3, wherein: the first amplifying unit is arranged between the first input end and the second input end, and the second amplifying unit is arranged between the first input end and the second input end.

5. The hybrid modulated oscillator circuit of claim 4, wherein: the first filtering unit and the second filtering unit are both filters, and the first amplifying unit and the second amplifying unit are both triode circuits.

6. The hybrid modulation oscillator circuit according to any one of claims 1 to 4, wherein: the frequency control module comprises a singlechip circuit for generating crystal oscillator frequency and a phase-locked loop control circuit for locking the output crystal oscillator frequency.

7. The hybrid modulated oscillator circuit of claim 6, wherein: first frequency oscillation circuit includes triode T12, triode T12's base links to each other with the phase-locked loop control circuit output through inductance, electric capacity and diode VD2 of establishing ties, diode VD 2's positive pole with triode T12's base links to each other, the projecting pole of triode passes through inductance L22 and the resistance R41 ground connection of establishing ties, triode T12's collecting electrode connects the power respectively and exports oscillating signal.

8. The hybrid modulated oscillator circuit of claim 7, wherein: and a feedback end FIN is also led out from the output end of the triode T12 and is connected with the feedback input end of the phase-locked loop control circuit.

9. The hybrid modulation oscillator circuit according to any one of claims 1 to 4, wherein: the frequency mixing circuit comprises a local oscillator amplification and isolation unit and a frequency division unit, wherein the frequency division unit is respectively connected with the output end of the local oscillator amplification and isolation unit and the output end of the IF intermediate frequency signal, and is used for mixing and modulating two paths of signals and outputting a set frequency signal.

10. The hybrid modulated oscillator circuit of claim 9, wherein: the local oscillator amplification isolation unit comprises a triode T21 and peripheral devices thereof, the base electrode of the triode T21 is connected with the output end of the first frequency oscillation circuit and one end of a resistor R38 respectively, the resistor R38 is connected with a power supply after being connected with an inductor L26 and a resistor R64 in series, the emitter electrode of the triode T21 is grounded, and the collector electrode of the triode T21 is connected between the input end of the frequency division unit and the inductors L26 and the resistor R38 respectively.