JP2954001B2 - DTMF signal transmission wireless telephone device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless telephone apparatus for transmitting DTMF signals, and more particularly to a key for inputting a number.
A sound generating means for generating sound for confirming the key number input operation; and a D corresponding to the key number input operation.
DTMF signal generating means for generating a TMF signal;
The present invention relates to a DTMF signal transmission wireless telephone device that modulates a generated DTMF signal into a radio frequency signal and transmits the signal.

[0002]

2. Description of the Related Art A conventional DTMF signal transmitting radio telephone apparatus of this type is configured as shown in FIG. The DTMF signal generation circuit 4 is a circuit for generating a DTMF signal corresponding to the type of the input key 1, and the sounder amplifier 8 is a circuit for driving a sounder 9 which emits a key press confirmation sound when the key 1 is pressed. When the key 1 is pressed during a call, a key confirmation sound is emitted by the sounder 9 and at the same time, a DTMF signal is immediately generated by the DTMF signal generation circuit 4, the voltage control oscillator 5 is modulated, and the power module 6 and the antenna 7 perform the DTMF signal. Is sent. Therefore, as shown in FIG.
A signal is sent.

[0003]

Generally, a voltage controlled oscillator used in a PLL frequency synthesizer circuit of a radio telephone device or the like is easily affected by disturbances such as power supply noise, and noise is generated when a key is pressed. easy. For example,
This will be described with reference to the wireless telephone device 20 shown in FIG. When the key 1 is pressed, a key confirmation sound is sounded by the sounder 9, but a large current flows through the sounder amplifier 8 to sound the sounder 9. In a portable telephone, the current of the sounder amplifier 8 generally flows about 3 mA in a steady state, and about 30 mA when the sounder 9 is sounding. The large current and the current fluctuation affect the GND (ground) pattern, the power supply system, and the like, and enter the voltage controlled oscillator 5 as noise. It is particularly susceptible to effects when the packaging density is high, such as in small mobile phones. FIG. 4 is a timing chart showing the operation at this time. As shown in (a) to (c), at the same time as the key 1 is pressed, the sounder 9 is sounded with a large current of the sounder amplifier 8 (the energizing time S for sounding).
(T is generally about 100 to 200 msec), and the noise caused by the key press as described above is generated as shown in FIG.
In the conventional method, the DTMF signal is generated at the output of the DTMF signal generation circuit 4 almost at the same time when the key is pressed as shown in (e) (the generated time MT is 100 msec).
The noise is added to the DTMF signal in the modulated wave component of the output of the voltage controlled oscillator 5 as shown in (f) and (g), and the power module 6 and the antenna 7 together with the noise. Will be sent out. As described above, in the conventional method, noise generated when a key is pressed (when a confirmation sounder sounds) affects the voltage-controlled oscillator and is transmitted with noise added to the DTMF signal. / N is deteriorated, and the DTMF signal is erroneously transmitted.

[0004]

According to the present invention, there is provided a key for inputting a number, a sound generating means for generating a sound for confirming the number input operation of the key, and a sound generating means for responding to the number input operation of the key. DTMF signal generating means for generating a DTMF signal, and modulating the generated DTMF signal into a radio frequency signal and transmitting the signal. At least between the key and the DTMF signal generating means, The DTM corresponds to a period from when the number input operation of the key is recognized to when the supply of the driving power for sound generation of the sound generating means is stopped by the number input operation.
Means are provided for delaying the generation of the DTMF signal by the F signal generation means.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, and shows only parts related to the present invention.
The difference between the wireless telephone device 10 of the present embodiment and the conventional wireless telephone device 20 shown in FIG. 3 is that a key input between the key 1 and the DTMF signal generation circuit 4 for recognizing that the key 1 is pressed. A recognition means 2 and a time difference generation means 3 for delaying the generation of the DTMF signal of the DTMF signal generation circuit 4 until the supply of a large current to the sounder amplifier 8 for sounding the sounder 9 after the key input is recognized is stopped. It is to have. In addition, circuit blocks denoted by the same reference numerals as in FIG. 3 have the same functions and configurations. Further, detailed circuit configurations for performing telephone communication and wireless transmission / reception can be realized by well-known techniques, and thus illustration and description are omitted. The key input recognizing means 2 and the time difference generating means 3 are realized by a CPU and a program constituting a control unit (not shown) of the wireless telephone device 10.

Next, the operation will be described with reference to FIGS. 2 (a) to 2 (g) which show the operation timing of each section together with FIG.

When key 1 is pressed during a call (FIG. 2)
(A)) The key input is recognized by the key input recognizing means 2 and the time difference DT is calculated from the key input by the time difference generating means 3.
And a DTMF signal is generated by the DTMF signal generation circuit 4 (FIG. 2E: MT about 100 msec).
c). Then, the voltage controlled oscillator 5 is modulated by the DTMF signal (FIG. 2F), and the power module 6 and the antenna 7 transmit the DTMF signal. (Figure 2
(G)). On the other hand, at the same time when the key 1 is pressed, a key confirmation sound is emitted by the sounder amplifier 8 and the sounder 9 (FIG. 2C). Here, a large current flows through the sounder amplifier 8 to sound the sounder 9 (FIG. 2B: about 30 m).
A), the large current and the current fluctuation affect the GND pattern, the power supply system, and the like, and become noise to enter the voltage controlled oscillator 5. However, here, the time difference DT generated by the time difference generating means 3 is defined as the time from the input of the key 1 as shown in FIG. 2E to the end of the sounding of the key confirmation sound, that is, the large current supply time ST to the sounder amplifier 8 . 2 (f) and (g), the output of the voltage controlled oscillator 5 can transmit a clear DTMF signal without being affected by noise.

[0008]

The DTMF signal transmitting radio telephone apparatus of the present invention recognizes a key number input operation and stops supplying drive power for generating a sound for confirming key operation which causes noise. Since the generation of the DTMF signal is delayed, a clear DTMF signal can be transmitted without being affected by noise generated when a key is pressed, and the DTMF signal can be transmitted accurately.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing operation timings of each unit of the wireless telephone device of FIG. 1;

FIG. 3 is a block diagram illustrating a configuration example of a conventional wireless telephone device.

FIG. 4 is a diagram showing operation timings of respective parts of the wireless telephone device of FIG. 3;

[EXPLANATION OF SYMBOLS] 1 Key 2 Key input recognition means 3 time difference generating means 4 DTMF signal generating circuit 5 the voltage controlled oscillator 8 sounder amplifier 9 Sa und 10 radiotelephone

Claims (1)

(57) [Claims] 1. A key for inputting a number, a sound generating means for generating a sound for confirming the number input operation of the key, and a DTMF signal for generating a DTMF signal corresponding to the key input operation of the key Generating means for modulating the generated DTMF signal into a radio frequency signal and transmitting the signal.
In the MF signal transmitting wireless telephone device, the key and the D
Between the TMF signal generating means, at least period from recognizes the number input operation to supply the sound generating driving power for said sound generation means according to the number input operation is stopped the key, the DTMF signal DTM by generating means
A DTMF signal transmitting wireless telephone device comprising means for delaying generation of an F signal.