CN1156389A - Microphone - Google Patents
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- CN1156389A CN1156389A CN 96121657 CN96121657A CN1156389A CN 1156389 A CN1156389 A CN 1156389A CN 96121657 CN96121657 CN 96121657 CN 96121657 A CN96121657 A CN 96121657A CN 1156389 A CN1156389 A CN 1156389A
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- tone signal
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Abstract
A microphone includes a power supply output generating means for generating a power supply output of predetermined voltage; a tone signal generating means; a sound electric signal converting means; a mixing means for mixing the sound signal obtained by the sound electric signal converting means and the tone signal; a modulating means for modulating a carrier wave with a low frequency signal consisting of the sound signal and tone signal which are mixed by the mixing means; and a transmitting means for transmitting modulated wave signal modulated by the modulating means in an electric wave, and wherein the tone signal generating means generates the tone signal having predetermined frequency and predetermined frequency deviation such as not to extend across predetermined frequency bandwidth of the carrier wave, and the voltage generating means generates the power supply output of predetermined voltage on the basis of the output of the power supply unit by using the tone signal as a clock.
Description
The present invention relates to microphone, particularly be applicable to the microphone of the portable microphone of band wireless system.
In the portable microphone of band wireless system, for example, as power supply, if the dry cell of usefulness is normal voltage just, then this phenomenon can occur with dry cell: when the voltage landing occurring, output voltage descends, and dynamic range reduces.
Therefore,, must make the dry cell voltage transition become to start the predetermined dc voltage of microphone, (being the power supply of 5 volts microphone as starting voltage for example) with 3 volts dry cell for preventing that output voltage from descending and dynamic range reduces.Thereby, in microphone, be the dc voltage that obtains to be scheduled to, use DC-DC transducer (DC transformer), it has PWM (pulse width modulation) pattern, and PWM uses the frequency of oscillation of 100 to 180 (KHz) of internal oscillator circuit generation.In fact, in the DC-DC transducer, carry out pulse width modulation with internal oscillator circuit, for example, frequency of oscillation is 100 (KHz).
Therefore, in the microphone of said structure was arranged, the frequency of oscillation 100 (KHz) that the DC-DC transducer produces according to internal oscillator circuit produced predetermined dc voltage, and the frequency of oscillation 100 (KHz) of selection is superimposed on the carrier wave by power line or by magnetic leakage flux.
For example, as shown in Figure 1, the channel cycle of supposing microphone and receiver is 250 (KHz), and the first-harmonic inversion frequency that oscillating circuit produces in the DC-DC transducer is 100 (KHz), and first-harmonic is superimposed on the carrier wave.Therefore, such problem has appearred, the 2nd high order harmonic component (200KHz) of first-harmonic and the 3rd high order harmonic component (300KHz) exert an influence by expanding to the channel occupied bandwidth adjacent with its left and right sides, and simultaneously, the 2nd has become the interference radio wave on the receiver with the 3rd high order harmonic component.
As mentioned above, in the microphone,, must be provided for reducing the filter of frequency of oscillation because unwanted frequency of oscillation 100 (KHz) is superimposed on the carrier wave by the power line that the DC-DC transducer comes.But on the circuit structure of microphone, because the substrate size is limited, thereby the use of filter is restricted.Thereby, occurred being superimposed to and caused unwanted (spuious) emission problem on the carrier wave with the frequency component that filter reduces.
Consider described problem, the objective of the invention is, a kind of microphone that reduces unwanted emission with simple structure is provided.
The microphone that provides can be realized described purpose of the present invention and other purpose, and it comprises: power supply output generating means, and it produces the power supply output of predetermined voltage according to the output of supply unit; Tone signal generating device, it is by the output services of supply unit and produce tone signal; The sound electrical signal conversion device is used to convert tones into the signal of telecommunication; Mixer device will be by the voice signal and the tone signal mixing of sound electrical signal conversion device acquisition; Modulating device, it uses the low frequency signal modulated carrier through the voice signal of mixer device mixing and tone signal formation; And dispensing device, send the ripple signal of modulating through modulating device with electric wave; Wherein, tone signal generating device produces the tone signal that preset frequency and predetermined frequency offset are arranged, and predetermined frequency shift (FS) is no more than the predetermined frequency band width of carrier wave; Power supply output generating means tone signal is the output of clock according to supply unit, produces the power supply output that predetermined voltage is arranged.
Like this, with the clock of tone signal generating device as power supply output generating means, have preset frequency and predetermined frequency offset with tone signal generating device output are no more than the tone signal of predetermined occupied bandwidth, then microphone can related this tone signal generating device, because many higher harmonic components are extremely low, even the frequency component of tone signal is superimposed upon on the carrier wave, unwanted emission also can be reduced and not influence adjacent channel.
Seen below in conjunction with the accompanying drawing detailed description of the invention, will more be expressly understood characteristic of the present invention, principle and purposes.The similar numeral of similar part in the accompanying drawing.
Fig. 1 is the schematic diagram that concerns of the carrier wave of prior art and high order harmonic component;
Fig. 2 is the microphone structure block diagram that comprises tone signal generation circuit by of the present invention;
Fig. 3 is the schematic diagram that concerns of carrier wave and high order harmonic component.
It is as follows that preferred embodiments of the invention will now be described with reference to the accompanying drawings:
Among Fig. 2, numeral 10 expressions have the structure of the portable microphone of FM modulating system.When mains switch 11 forwarded ON to, the tone signal generation circuit 14 in the tone signal generation part 13 started with the output of supply unit 12 as tone generation device.
Tone signal generation circuit 14 is to having external clock input and as the tone signal S1 of DC-DC transducer 15 outputs 32 (KHz) of power supply output generating means, also tone signal S1 being supplied with low frequency amplifier 16.
S1 makes clock with 32 (KHz) tone signal, and the DC-DC transducer 15 of band external clock input carries out pulse-width modulation according to the output of supply unit 12, can produce the power supply output of predetermined voltage.Therefore, microphone 10 can use the power supply output of the predetermined voltage of DC-DC transducer 15 generations of being with the external clock input to start every block part (not shown).
At this point, tone signal S1 is the signal that prevents to export unwanted voice signal, even in waiting for receiving course, receiver has been received the signal of unwanted upper frequency, also need not open the noise suppression circuit (not shown).That is tone signal S1 superposition first-harmonic on carrier wave.The frequency that first-harmonic has is no more than the predetermined occupied bandwidth of carrier wave, and is the frequency shift (FS) of being scheduled to, and does not comprise the frequency of audio band, for example, and the frequency of 32 (KHz).
At this point, suppose that the maximum of voice signal frequency is " fmax ", the frequency shift (FS) of tone signal S1 is " Δ f ", occupied frequency bandwidth " B " is represented with following formula:
B＝2(fmax+Δf) (1)
That is, the peak frequency " fmax " of supposing voice signal is 15 (KHz), and frequency departure " Δ f " is 40 (KHz), presses equation (1), and occupied bandwidth " B " is 110 (KHz).
On the other hand, frequency shift (FS) is the width that the first-harmonic of the tone signal S1 of 32 (KHz) is offset.Offset width is the size of tone, i.e. volume.
Thereby if the frequency departure of tone signal S1 is too big, it may surpass the occupied bandwidth of carrier wave, so it can not be too big.Otherwise if the frequency shift (FS) of tone signal S1 is too little, tone signal S1 is by the noise mixing that produces in the transmission of space, and then tone signal S1 can not identify on receiver.
Therefore, must make frequency shift (FS) that a definite scope is arranged, among the present invention, the tone signal S1 of 32 (KHz) and does not comprise the frequency of audio band in the occupied bandwidth of carrier wave, and has predetermined frequency shift (FS).
In addition, because receiver detected pitch signal S1, with control noise control circuit, when microphone 10 is sent the tone signal S1 that is superimposed on the carrier wave, during the receiver reception carrier, receiver differentiates whether the tone signal S1 of 32 (KHz) is superimposed on the carrier wave then.At this moment, be not superimposed on the carrier wave if receiver is judged the tone signal S1 of 32 (KHz), sound can not sent from loud speaker.If receiver is judged the tone signal S1 superposition of 32 (KHz) on carrier wave, sound is exported from loud speaker.
On the other hand, low frequency amplifier 16 amplifies tone signal S1, so the amplification level of tone signal S1 is higher than the level of predetermined threshold voltage, this predetermined threshold voltage is used for judging at receiving terminal whether tone signal S1 is superimposed to carrier wave, and it is outputed to inverter 17 as tone signal S2.Because low frequency amplifier 16 can amplify tone signal S1, so the amplification level of tone signal S1 (corresponding to the frequency shift (FS) of high frequency) can not be lower than threshold voltage.
Inverter 17 is frequency shift (FS) stabilizing arrangements, it is to the ripple shaping of the tone signal S2 that is amplified to the amplitude leyel that is higher than predetermined threshold voltage, with the amplitude leyel (frequency shift (FS)) of steady sound tonal signal S2, and it is outputed to low pass filter 18 as tone signal S3.
The high order harmonic component of low pass filter 18 filtering tone signal S3 with control high order harmonic component skew, and is exported to low frequency mixer 19 as mixer device with its stable tone signal S4 as 32 (KHz) constant amplitude.
In this way, convert tones into the signal of telecommunication, then, output to low frequency amplifier 21 as voice signal S5 as the microphone 20 of sound electrical signal conversion device.Low frequency amplifier 21 is amplified to predetermined level with voice signal S5, so that it is outputed to low frequency mixer 19 as low frequency signal S6.
Hang down the tone signal S4 and the low frequency signal S6 of frequency mixer 19 mixing 32 (KHz), and it is outputed to modulator 22 as low frequency signal S7.Modulator 22 usefulness low frequency signal S7 FM-modulated carriers, and it is outputed to high-frequency amplifier 23 as high-frequency signal S8.High-frequency amplifier 23 is amplified to predetermined level with high-frequency signal S8, and it is outputed to external equipment as electric wave by antenna 24.
In the said structure, in the microphone, low frequency mixer 19 will be by tone signal S4 and the low frequency signal S6 mixing of 32 stable (KHz) of predetermined frequency offset by tone signal generation part 13, then mixed frequency signal is exported by modulator 22, high-frequency amplifier 23 and antenna 24, thus, the frequency of oscillation of the tone signal S1 of superposition on carrier wave is remained in the occupied bandwidth of carrier wave.
Thereby, as shown in Figure 3, under the first-harmonic of the converter frequencies of 32 (KHz) is superimposed to situation on the carrier wave, when it becomes the 2nd high order harmonic component 64 (KHz), the 3rd high order harmonic component 96 (KHz) ... when the 6th high order harmonic component 192 (KHz) and the 7th high order harmonic component 224 (KHz), the level of high order harmonic component is multiple low, thereby the 7th high order harmonic component is in the occupied bandwidth of adjacent channel.But level is extremely low.
Thus, in the microphone 10, the 7th high order harmonic component does not influence adjacent channel, and it can be as disturbing radio wave to be prevented from receiver.
And, in the microphone 10, the DC-DC transducer 15 of band external clock input receives the tone signal S1 that also is used as clock from tone signal generation circuit 14, thus, the frequency of oscillation of the oscillating component of each circuit block (for example cpu clock signal or LCD vibration) is synchronous with the frequency of oscillation of tone signal S1.Because the frequency of oscillation of other oscillating part and the frequency of oscillation of tone signal S1 are synchronous, so can not produce interference in the microphone 10, so, can suppress vibration and produce.
And the tone signal S1 of microphone 10 usefulness 32 (KHz) makes clock, produces the power supply output that predetermined voltage is arranged of supplying with each circuit block.Therefore, need not be used for reducing to be superimposed to the filter of the high fdrequency component on the power line, this has the power supply output of predetermined voltage different with 100 (KHz) frequency of oscillation generation that produces with internal oscillator circuit of prior art.
And in the microphone 10, DC-DC transducer 15 usefulness of band external clock input are made clock by the tone signal S1 of 32 (KHz) that external tone signal generating circuit 14 is supplied with, therefore, can simplify circuit structure.
And, in the microphone 10,32 (KHz) frequency of the first-harmonic that is produced by DC-DC transducer 15 vibrations of band external clock input remains in the occupied bandwidth of carrier wave of frequency shift (FS), and, the frequency that does not contain audio band, therefore, this frequency does not influence adjacent channel, can not allow the people hear noise yet.
And the low frequency amplifier 16 in the tone signal generation part 13 amplifies tone signal S1 to the amplitude leyel that is higher than predetermined threshold voltage, produces tone signal S2, and then, the amplitude leyel of inverter 17 steady sound tonal signal S2 produces tone signal S3.Therefore, the frequency shift (FS) of energy steady sound tonal signal S3.And the high fdrequency component of low pass filter 18 filtering tone signal S3 constitutes near sinusoidal wave tone signal S4.In the microphone 10,, thus, can control the distortion of the high order harmonic component of low frequency signal S7 near sinusoidal wave tone signal S4 and the low frequency signal S6 mixing that obtains by microphone 20.
By described structure, in the microphone 10, the tone signal S1 of the DC-DC transducer 15 usefulness predetermined frequency offset of band external clock input makes the clock of 32 (KHz), this predetermined frequency offset is no more than the occupied bandwidth of carrier wave, thus, even the first-harmonic of tone signal S1 is superimposed on the carrier wave, the level of many high order harmonic components becomes extremely low, also can not influence adjacent channel.That is, in the microphone 10, can the simple microphone that also can reduce unwanted emission of implementation structure.
Note, among the described embodiment, the frequency of oscillation of setting the tone signal S1 of tone signal generation circuit 14 generations is 32 (KHz), but, the invention is not restricted to this, tone signal S1 also as the various frequencies of oscillation of 31 (KHz), 33 (KHz) or 34 (KHz) only otherwise comprise the frequency of audio band, and remains in the occupied bandwidth of the carrier wave that comprises frequency shift (FS).In this case, also can obtain the effect identical with described embodiment.
And, among the described embodiment, microphone 10 has structure as shown in Figure 2, but, the invention is not restricted to this, microphone can have various structures, as long as the tone signal S1 that tone signal generation circuit 14 is produced is added to the DC-DC transducer 15 of band external clock input, and the frequency of oscillation of tone signal S1 is remained in the occupied bandwidth of carrier wave of frequency shift (FS) get final product.
And the present invention is applicable to the microphone 10 as microphone of FM modulating mode.But, the invention is not restricted to this, the present invention also can be used for the microphone by the transmission of PM modulating mode.
And the present invention is used for the portable microphone 10 as microphone, but the invention is not restricted to this, and it also can be used for various transmitters, as transmitter-receiver.
As mentioned above, comprise by microphone of the present invention: power supply output generating means, it produces the power supply output that predetermined voltage is arranged according to the output of supply unit; Tone signal generating device, it is according to the output services of supply unit, and the generation tone signal; The sound electrical signal conversion device is used for sound is transformed into the signal of telecommunication; Mixer device, it will be by the voice signal and the tone signal mixing of sound electrical signal conversion device acquisition; Modulating device is with the voice signal of mixer device mixing and the low frequency signal modulated carrier of tone signal formation; And dispensing device, it sends the modulation wave signal of being modulated by modulating device with the electric wave form, wherein tone signal generating device produces the tone signal that preset frequency and predetermined frequency offset are arranged, this predetermined frequency offset is no more than the preset frequency bandwidth of carrier wave, and voltage generation circuit is the power supply output that clock generating has predetermined voltage according to the output tone signal of supply unit.
Therefore, with the clock of tone signal generating device as power output apparatus, with having preset frequency and predetermined frequency offset to be no more than the tone signal of predetermined occupied frequency bandwidth, microphone can have tone generation device, even the frequency component of tone signal is superimposed on the carrier wave, because many higher harmonic components are extremely low, the microphone that can reduce unwanted emission and not influence adjacent channel is attainable.
Although the present invention has been described in conjunction with the preferred embodiments, obviously,, also have various variations and remodeling to the technical staff of the industry, they all do not break away from the present invention's spirit and claimed scope.
Claims (3)
1, a kind of microphone comprises:
Power supply output generating means, it produces the power supply output that predetermined voltage is arranged according to the output of supply unit;
Tone signal generating device, it is according to the described output services of described supply unit, and the generation tone signal;
The sound electrical signal conversion device, it is transformed into the signal of telecommunication with sound;
Mixer device is with the voice signal and the described tone signal mixing of described sound electrical signal conversion device acquisition;
Modulating device, it is with comprising the described voice signal of described mixer device mixing and the low frequency signal modulated carrier of described tone signal; With
Dispensing device, it sends the modulation wave signal of modulating with modulating device with electric wave;
It is characterized in that:
Described tone signal generating device, producing has preset frequency and predetermined frequency offset to be no more than the described tone signal of the preset frequency bandwidth of described carrier wave;
Described power supply output generating means according to the output of described supply unit, is made clock with described tone signal, produces the described power supply output that predetermined voltage is arranged.
2, by the microphone of claim 1, it is characterized in that described tone signal generating device has the frequency shift (FS) stabilizing arrangement, be used to stablize described frequency shift (FS).
3, by the microphone of claim 1, it is characterized in that described tone signal does not contain the frequency of audio band.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96121657 CN1156389A (en) | 1995-11-07 | 1996-11-07 | Microphone |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP313524/95 | 1995-11-07 | ||
| CN 96121657 CN1156389A (en) | 1995-11-07 | 1996-11-07 | Microphone |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1156389A true CN1156389A (en) | 1997-08-06 |
Family
ID=5126972
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 96121657 Pending CN1156389A (en) | 1995-11-07 | 1996-11-07 | Microphone |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1156389A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110850786A (en) * | 2019-12-03 | 2020-02-28 | 徐汇 | Automatic change equipment remote control system |
-
1996
- 1996-11-07 CN CN 96121657 patent/CN1156389A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110850786A (en) * | 2019-12-03 | 2020-02-28 | 徐汇 | Automatic change equipment remote control system |
| CN110850786B (en) * | 2019-12-03 | 2020-10-16 | 徐汇 | Automatic change equipment remote control system |
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| PB01 | Publication | ||
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| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |