CN201118886Y - Frequency conversion inter-speaker with small step value - Google Patents

Abstract

The utility model discloses a walkie talkie, in particular to a walkie talkie circuit with radio frequency and beat frequency. The walkie talkie circuit comprises a central control module, and an input module, a frequency regulating module, an audio frequency input module and an audio frequency output module which are connected on the central control module, a power supply module supplies power for all the modules, the frequency regulating module comprises an MCU, a phase-locked loop, a crystal oscillator, a low pass filter and a voltage controlled oscillator, wherein, one circuit of the voltage controlled oscillator feeds back oscillation output signals to the phase-locked loop, the other circuit outputs radio-frequency signals, and the reference frequency of the crystal oscillator is provided for the phase-locked loop. The walkie talkie circuit ensures the walkie talkie to meet the stepping requirement of the 2.5 KHz frequency stepping value on the basis of supporting the 5 KHz monolithic processor, and ensures the walkie talkie not to generate self excitation caused by 2.5 KHz stepping to lead to squealing of the walkie talkie to affect the operation of the walkie talkieg.

Description

The intercom of little step value frequency conversion

Affiliated technical field

The utility model discloses a kind of intercom, particularly a kind of intercom circuit of little step value frequency conversion.

Background technology

Intercom is easy to use, cheap with it, the conversation low cost and other advantages widely people known, and in the extensive use of every profession and trade field.Intercom of the prior art all is to adopt the height of frequency to distinguish communications band in the permission communications band of finite width, the differentiation of communications band is again to adopt step value to distinguish, there is the frequency step value of 2.5KHz, 5KHz, 6.25KHz in the intercom industry at present, and general intercom all is to adopt 5KHz, 6.25KHz to distinguish communication frequency as the frequency step value.But need the frequency step value of 2.5KHz as intercom in some occasion and client, most intercoms when directly using 2.5K frequency step value, often exist locking time long, also can produce self-excitation sometimes and cause that intercom is uttered long and high-pitched sounds etc. and influence the shortcoming of intercom use, if, can increase product cost again by selecting for use the higher phase lock circuitry of performance to solve this problem.

Summary of the invention

When directly using 2.5K frequency step value, often exist locking time long at the above-mentioned intercom of mentioning, sometimes also can produce self-excitation causes that intercom is uttered long and high-pitched sounds etc. and influences the shortcoming that intercom uses, if by selecting for use the higher phase lock circuitry of performance to solve this problem, can increase the present situation of product cost again, the utility model provides a kind of new intercom circuit structure, the MCU of the frequency adjustment module in the intercom circuit is connected with phase-locked loop with clock interface by data, phase-locked loop rear pump electric current is to low pass filter, low pass filter output fixed voltage is to voltage controlled oscillator, voltage controlled oscillator one tunnel feedback oscillation outputs signal to phase-locked loop, another road output radiofrequency signal, the crystal oscillator reference frequency is given phase-locked loop.

The technical scheme that its technical problem that solves the utility model adopts is: a kind of intercom of little step value frequency conversion, comprise shell and setting intercom circuit in the enclosure, the intercom circuit comprises central control module and the input module that is connected on the central control module, frequency adjustment module, the audio frequency input module, the audio frequency output module, power module is given each module for power supply, frequency adjustment module comprises MCU, phase-locked loop, crystal oscillator, low pass filter, voltage controlled oscillator, MCU is connected with phase-locked loop with clock interface by data-interface, phase-locked loop rear pump electric current is to low pass filter, low pass filter output fixed voltage is to voltage controlled oscillator, voltage controlled oscillator one tunnel feedback oscillation outputs signal to phase-locked loop, another road output radiofrequency signal, the crystal oscillator reference frequency is given phase-locked loop.

The technical scheme that its technical problem that solves the utility model adopts further comprises:

It is the crystal oscillator of 12.8MHz that described crystal oscillator adopts frequency of oscillation.

Described phase-locked loop adopts ADF4111.

The beneficial effects of the utility model are: the utility model adopts the single-chip microcomputer of supporting 5KHz, do not increasing the requirement that makes intercom satisfy the stepping of 2.5KHz frequency step value on the basis of manufacturing cost, making intercom can not cause intercom to utter long and high-pitched sounds, influence the intercom use because of the 2.5KHz stepping produces self-excitation.

Below in conjunction with the drawings and specific embodiments the utility model is described further.

Description of drawings

Fig. 1 is the utility model frequency adjustment module circuit box structure schematic diagram.

Embodiment

Present embodiment is the utility model preferred implementation, and other all its principles are identical with present embodiment or approximate with basic structure, all within the utility model protection range.

The utility model is the improvement to existing intercom, existing intercom comprises shell and setting intercom circuit in the enclosure, existing intercom circuit comprises central control module, input module, the audio frequency input module, the audio frequency output module, input module is connected with data-interface on the central control module, be used for information such as input communication frequency range, the audio frequency input module, the audio frequency output module is connected with data-interface on the central control module, the input and output of voice messaging when being used to converse, power module is given each module for power supply in the intercom, above-mentioned each intercom is formed module and is adopted intercom module of the prior art to get final product, also include frequency adjustment module in the intercom circuit, frequency adjustment module is used for frequency range and regulates.

Please referring to accompanying drawing 1, the core component of frequency adjustment module is a MCU, and in the present embodiment, MCU adopts M30620 type single-chip microcomputer, also can adopt other models or Series chip to substitute as it in concrete the enforcement.MCU is connected with Phase Lock Loop IC 9 with clock line by data wire, in the present embodiment, the Phase Lock Loop IC 9 concrete models that provide are ADF4111, during concrete enforcement, also can adopt the phase-locked loop of other models, MCU provides reference frequency by data wire and clock line, data such as divider ratios are to Phase Lock Loop IC 9, be connected with a low pass filter LPF on the Phase Lock Loop IC 9, Phase Lock Loop IC 9 provides a pump electric current (promptly being that the pulse signal that phase-locked loop is exported is converted to the voltage signal that is similar to direct current) to give low pass filter LPF, be connected with voltage controlled oscillator VCO on the low pass filter LPF, low pass filter LPF provides a fixed voltage to voltage controlled oscillator VCO, change the output frequency size of voltage controlled oscillator VCO by the size that changes its magnitude of voltage, oscillating current of voltage controlled oscillator VCO output provides rf frequency to intercom, is gone out by aerial radiation.Frequency of oscillation of voltage controlled oscillator VCO feedback is given Phase Lock Loop IC 9.Be connected with quartz oscillator X4 on the Phase Lock Loop IC 9, quartz oscillator X4 is the reference frequency crystal, provide a reference frequency to Phase Lock Loop IC 9, MCU provides voltage VC to quartz oscillator X4 by the D/A mouth, in the present embodiment, quartz oscillator X4 adopts the quartz oscillator of 12.8MHz.

Below in conjunction with instantiation, advantage of the present utility model is described.

1) when using 5KHz as the frequency step value, for example to export the rf frequency of 400.00MHz, then MCU exports corresponding 400.00MHz control data and gives Phase Lock Loop IC 9 (ADF4111), send VC1 voltage simultaneously and give quartz oscillator X4, make quartz oscillator X4 provide a reference frequency to Phase Lock Loop IC 9, Phase Lock Loop IC 9 output respective pump Current Control voltage controlled oscillator VCO make the voltage controlled oscillator VCO vibration at 400.00MHz, and output.

2) when needs use 2.5KHz as step value, it is the frequency step value that its essence still adopts 5KHz, only need to change the voltage VC that exports quartz oscillator X4 to by MCU, change the reference frequency value that quartz oscillator X4 provides, with its reference frequency value that provides skew 2.5KHz, can cooperate 5KHz to realize the 2.5KHz step value for the frequency step value.As realize exporting the rf frequency value of 400.0025MHz, MCU changes to magnitude of voltage VC2 by the magnitude of voltage VC1 that will send to quartz oscillator X4, the reference frequency that makes quartz oscillator X4 offer Phase Lock Loop IC 9 improves 2.5KHz on former basis, Phase Lock Loop IC 9 output respective pump Current Control voltage controlled oscillator VCO, make the voltage controlled oscillator VCO vibration at 400.0025MHz, and output, make frequency of oscillation to upper deviation 2.5KHz, realized the purpose of 2.5KHz stepping thus by the 5KHz stepping, the problem when having solved the 2.5KHz stepping simultaneously.

In the intercom of the bottom single-chip microcomputer that it is stepping that the utility model can be widely used in various support 5KHz of the prior art, realized the purpose of 2.5KHz stepping, the variety of issue that has been brought when having solved the 2.5KHz stepping simultaneously.

Claims (3)

1, a kind of intercom of little step value frequency conversion, comprise shell and setting intercom circuit in the enclosure, the intercom circuit comprises central control module and the input module that is connected on the central control module, frequency adjustment module, the audio frequency input module, the audio frequency output module, power module is given each module for power supply, it is characterized in that: described frequency adjustment module comprises MCU, phase-locked loop, crystal oscillator, low pass filter, voltage controlled oscillator, MCU is connected with phase-locked loop with clock interface by data-interface, phase-locked loop rear pump electric current is to low pass filter, low pass filter output control voltage is to voltage controlled oscillator, voltage controlled oscillator one tunnel feedback oscillation outputs signal to phase-locked loop, another road output radiofrequency signal, the crystal oscillator reference frequency is given phase-locked loop.

2, the intercom of little step value frequency conversion according to claim 1 is characterized in that: it is the crystal oscillator of 12.8MHz that described crystal oscillator adopts frequency of oscillation.

3, the intercom of little step value frequency conversion according to claim 1 is characterized in that: described phase-locked loop adopts ADF4111.

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