JPS6096034A - Method for transmitting pulse signal in radio equipment - Google Patents

Abstract

PURPOSE:To obtain a pulse signal transmitting method not generating periodic noises by multiplying a pulse signal by an integral number of multiple or by one integral fraction of multiple to convert it into a signal having a frequency at out-band of audible frequency, transmitting the said converted signal in a radio equipment and extracting the pulse signal in the vicinity of a part requiring the pulse signal. CONSTITUTION:A clock pulse of 32kHz outputted from an oscillation circuit 2 is converted into a pulse of 4kHz by applying 1/8 frequency-devision at a frequency divider 11, the pulse of 4kHz is transmitted to a frequency 13 via a line l1, the 4kHz pulse is formed into a 1kHz pulse by frequency-dividing the 4kHz pulse into 1/4 and the signal is transmitted to an amplifier circuit 5 and a speaker 6 via lines l2 and l3. Furthermore, an output of the frequency divider 11 is transmitted to a microprocessor while being frequency-divided by 1/4 at the frequency divider 12 via a short line l4. On the other hand, the band other than 300kHz-3kHz is attenuated normally by a steep filter in the radio equipment (transmitter 8 and a receiver not shown), periodic noise in 4kHz is not sounded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a pulse signal transmission method within a wireless device,
In particular, the present invention relates to a device that prevents the generation of noise due to signals on a pulse signal transmission line.

[Technical background of the invention]

In recent years, more and more wireless devices are using microprocessors to perform complex control.

Along with this, a function is provided to play various notification sounds. The notification sound is generated by dividing a clock pulse normally used in a microprocessor to an audible frequency and applying this to a speaker.

FIG. 1 shows a conventional example of a notification sound generation circuit in such a radio device, in which a 32 KHz clock pulse generated from a clock pulse oscillation circuit 2 for driving a microprocessor 1 is input to the microprocessor 1, and The signal is input to a frequency divider 3, divided into IKHz, and used as an audible frequency oscillation source for notification sound. The output pulse of this frequency divider 3 is input to the microprocessor 1 for timing purposes, and the line! 8. The signal is inputted to the speaker 6 via the amplifier circuit 5 and is emitted as a notification sound. For example, when the key 7 is operated, the microprocessor 1 reads the data, performs predetermined arithmetic processing, outputs a signal a to the line 12 in response to the result of the processing, and thereby outputs a signal a to the amplifier circuit 5.
The audio frequency (IK,
Hz) to produce a sound. Further, the transmitter 8 transmits a signal to be transmitted from the antenna 9 using a signal of a predetermined frequency formed by the synthesizer 10 as a carrier wave in response to a command from the microprocessor 1.

[Problems with background technology]

Incidentally, the microprocessor 1 is usually mounted on a substrate (none of which is shown) together with other control circuits, and the clock pulse oscillation circuit 2 and frequency dividing circuit 3 are mounted near the substrate in order to drive the microprocessor I. On the other hand, since the speaker 6 is mounted on the housing and the amplifier circuit 5 is also mounted on the board near it, the frequency divider 3 and the amplifier circuit 5 are
The signal line (pattern or wiring) lI connecting the two becomes quite long. Moreover, since the frequency divider 3 is composed of, for example, a CMo;S device, and in this case its output is switched at an IKHz cycle, the high frequency impedance of the pattern 1 changes at an IKHz cycle. Here, if the length of the signal line II is long, the impedance changes there also are severe.

On the other hand, the antenna 9 that transmits the radio waves from the transmitter 8 is normally placed outside the housing which has a shielding effect, but due to the leakage of the transmission output within the housing, there is a standing wave from the transmitting power inside the housing. is standing. This standing wave is caused by the reflection of radio waves within the housing.

Note that this standing wave is also generated when part of the power radiated from the antenna 9 leaks into the housing when the shielding effect of the housing is insufficient. Naturally, when the antenna 9 is built into a device, the occurrence of the standing waves becomes even more pronounced.

It is known that the standing waves existing within the housing generate phase noise when they enter the synthesizer 10, which is the frequency source of the transmitter 80, for example. Furthermore, if the voltage jumps into a transistor or diode in another circuit part (not shown), it may be rectified and cause a DC potential change. This changes, for example, the output voltage of the power supply stabilization circuit.

However, if the standing waves are constant, the noise caused by these fluctuations will only slightly increase the thermal noise and will not be much of a problem.

However, as explained earlier, the rather long line l,
When the high frequency impedance is changed at a period of IKHz, the amount of radio wave reflection changes due to this pattern, so the standing wave changes at a period of 1KH2. Therefore, for example, the output of the synthesizer 10 has this period IKH.
z phase noise is generated.

As a result, this periodic noise is demodulated by the receiver receiving the transmission output of this radio and is heard. Although this noise usually does not significantly degrade the S/N,
Because it contains many Hz components, it is much more annoying than thermal noise. In general, this tendency becomes more pronounced as the wavelength increases.

In addition to the notification sound mentioned in the example, this type of noise can also be caused by data signals used for connection control, etc., which have a bit rate within the voice band, or dynamic lighting that lights up a light emitting display element at a cycle within the voice band. Occur.

Furthermore, if such a long line 7 is parallel to a line of an audio circuit (not shown) of the radio, the line may be directly coupled to the line and IKHz may leak as a beeping sound.

As described above, in conventional circuits, for example, IKHz sounds can be heard as noise, which has the problem of interfering with telephone calls and impairing the quality of the telephone calls. In particular, such noise is a problem when the radio equipment is downsized because standing waves are likely to occur due to the simplification of the shield, and this is a big problem in small radio equipment that includes the antenna 9.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above drawbacks and provide a method for transmitting pulse signals inside a wireless device that does not generate periodic noise during pulse signal transmission within the device.

[Summary of the invention]

The present invention provides a method for transmitting a pulse signal inside a wireless device that transmits a pulse signal having a frequency included in an audible frequency band. Convert to
Transmitting within the wireless device using the converted signal,
The above object is achieved by extracting the pulse signal by multiplying the transmitted signal by an integral number or an integral number in the vicinity of a location where the pulse signal is required.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows an embodiment of the present invention, and the circuit according to this embodiment includes a frequency divider 11 instead of the frequency divider 3 shown in FIG.
12 and 13 so that the signal transmitted over the long line 11 is outside the audible frequency band of the radio. In the following drawings, parts that perform the same functions as those shown in FIG. 1 are given the same reference numerals to simplify the explanation.

That is, according to this embodiment, a 32 KHz clock pulse outputted from the oscillation circuit 2 is converted into a 4KH2 pulse by dividing the frequency by 1/8 in the frequency divider 11, and this 4KHz pulse is sent to the line l. , through divider 1
This 4 KHz pulse is further divided into 1/4 to become an IKHz pulse, and then transmitted to the amplifier circuit 5 and speaker 6 via the short line A2.13. Further, the output of the frequency divider 11 is divided into four parts by a frequency divider 12 and transmitted to the microprocessor 1 via a short line 14. Therefore, the long line 11
Since pulses switching at 4 KHz are transmitted, the standing waves inside the radio change at a period of 4 KHz, and the periodic noise has a period of 4 KHz.

On the other hand, since the radio device (transmitter 8 and receiver, not shown) normally uses a steep filter to filter out frequencies other than 300 Hz to 3 KHz, this sound will not be emitted. Of course, even if this signal occurs in a line of an audio circuit (not shown) due to leakage between lines, no noise will be generated due to this signal.

FIG. 3 shows another embodiment of the invention. This embodiment is configured to transmit a section of a long line l using a 250 Hz pulse signal.

That is, the circuit according to this embodiment is constructed by inserting a frequency divider 14 and a multiplier 15 into the conventional circuit shown in FIG.
By dividing the frequency by 1/4 by 4, it is converted into a pulse of 2501 (Z), and this pulse of 2501-IZ is converted to a pulse of line l,
The 250 Hz pulse is multiplied by 4 to produce an IKHz pulse, which is then transmitted to the amplifier circuit 5 and speaker 6 via short lines 12 and 13.

Therefore, the period of periodic noise generated in this circuit is 25
014Z, and even if this periodic noise is demodulated on the receiving side, this sound will not be emitted because it is outside the audible frequency band (300 Hz to 3 KHz) of the radio. In addition,
In this case, leakage between patterns may generate noise consisting of harmonic components of the 250 Hz pulse signal, but if you want to solve the problem of harmonic components, you can further increase this frequency (
It is also possible to lower the frequency (250Hz). However, since the harmonic components are normally lower in level than the fundamental component, this does not pose a problem.

FIG. 4 shows yet another embodiment of the invention. In the circuit according to this embodiment, a radio wave received by an antenna 19 is demodulated by a receiving unit 18, and a frequency shift keyed data signal included in the demodulated signal is converted by a modem 17 into a signal using a non-return to zero method. . The modem 17 uses the output signal (usually several MHz) of the clock pulse oscillation circuit 16 to convert it into a 1200 bit/second non-return-to-zero signal, and this signal is a line! , to the microprocessor 1. For this reason, the microprocessor 1 requires a 1.2 KHz clock signal synchronized with the 1200 bits/second pulse to read the signal.

However, if the 1.2 KHz clock signal is directly transmitted to the microprocessor 1 via a long line, the 1.2 KHz clock signal will generate periodic noise within the voice band. Therefore, in this embodiment, 4
．． An 8 KHz pulse is transmitted from the modem 17 via line 17, and this 4.8 KHz pulse is input to the microprocessor 1 via a short line 18 by dropping the 4.8 KHz pulse by 1.2 KHz vc. As a result, the periodic noise generated in this device is 4.8KH2 outside the voice band.
This becomes a cycle, so you won't hear it.

〔Effect of the invention〕

As explained above, according to the present invention, a long signal line transmits a signal with a frequency outside the audible frequency band, and this signal is converted into a signal in the audible frequency band near the circuit that requires it. This audible frequency signal does not leak into the wireless line and deteriorate the call quality, allowing good communication.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a conventional wireless device using a microprocessor, Fig. 2 is a circuit diagram of a radio device to which one embodiment of the present invention is applied, and Fig. 3 is a circuit diagram of a radio device to which another embodiment of the present invention is applied. Circuit diagram of radio equipment FIG. 4 is a circuit diagram of a radio equipment to which still another embodiment of the present invention is applied. DESCRIPTION OF SYMBOLS 1... Microprocessor, 2, 16... Clock pulse oscillation circuit, 3, 11, 12, 13, 14
, 2f)... Frequency divider, 5... Amplifier circuit, 6...
Speaker, 7... Key, 8... Transmitter, 9.19.
...Antenna, 15... Multiplier, 17... Modem. Representative Patent Attorney Kensuke Norichika (1 idiot)

Claims (1)

[Claims] In a pulse signal transmission method within a wireless device that transmits a pulse signal with a frequency included in an audible frequency band, the pulse signal is converted to a signal with a frequency outside the audible frequency band by multiplying the pulse signal by an integer multiple or a fraction of an integer, The converted signal is transmitted within the wireless device, and the pulse signal is extracted by multiplying the transmitted signal by an integral fraction or an integral number in the vicinity of a location where the pulse signal is required. A pulse signal transmission method inside a wireless device, characterized in that: