JPH0615308Y2 - Keying circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a transmitter or a transceiver for generating a CW code by using a digital signal processing device, and particularly to residual noise and spurious noise when the electric key of a transmission radio wave is turned off. C
It relates to a keying circuit with improved W waveform.

[Prior Art] FIG. 3 shows an example of a transmitter that emits a CW code using a conventional digital signal processing device.

The disconnection information generated by the electronic key 1 is given to the digital signal processing device 2, and the digital signal processing device 2 generates a CW code according to the disconnection information.

The CW code is mixed with the oscillation frequency of the local oscillator 4 in the mixer 3 and becomes a frequency used for communication, that is, RF.

RF is amplified by RF amplifiers 5, 6 and 7 and is emitted as a radio wave from the antenna.

[Problems to be Solved by the Invention] In the conventional device described above, the noise generated from the digital signal processing device, the mixer noise, or the noise generated by the amplifier is caused because the amplifier in the subsequent stage from the mixer 3 is working even when the key is turned off. Is amplified as it is and is emitted from the antenna, so it will be output even if the electronic key is turned off.

In addition, spurious signals generated by the mixer from the signal of the local oscillator are also emitted as radio waves.

The present invention was made in view of the above points,
An object of the invention is to provide a keying circuit that does not emit residual noise and spurious when the key is turned off.

[Means for Solving the Problems] A keying circuit of the present invention is a transmitter or transceiver that converts a CW signal generated by using a digital signal processing device into a frequency used for communication and transmits the signal, and a keying information of a key. To a digital signal processing device to generate a CW code according to the intermittent information, and to activate an amplification unit that amplifies the signal of the converted frequency, at a rising edge to generate the CW code of the intermittent information of the electronic key, It is configured to be inoperative by a signal whose timing is shifted from the fall of the intermittent state.

[Operation] According to the keying circuit of the present invention, since the amplifier for amplifying the signal converted to the frequency used for communication, that is, the RF, is interrupted by the interrupt information of the key, noise and spurious are not emitted when the key is turned off.

Further, since the amplifier is turned off after a predetermined time has passed since the key was turned off, the falling portion of the CW code is not cut and key click is prevented.

[Embodiment] A keying circuit according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

The disconnection information generated by the electronic key 1 is given to the digital signal processing device 2, and the digital signal processing device 2 generates a CW code according to the disconnection information.

The CW code is mixed with the oscillation frequency of the local oscillator 4 in the mixer 3 and becomes a frequency used for communication, that is, RF.

RF is amplified by RF amplifiers 5, 6 and 7 and is emitted as a radio wave from the antenna.

The intermittent information of the electronic key 1 is also transmitted to the RF through the timing circuit 8.
Turn the amplifier 6 on and off.

A time chart of the above signals is shown in FIG. (A) shows the key waveform, and (b) shows the CW waveform generated in the digital signal processing device. The rising and falling portions of the CW waveform are shaped to reduce clicks.

The on / off keying waveform of the RF amplifier 6 is shown in (c).

As shown in the figure, the timing circuit is turned off after a delay of t time from when the electronic key is turned off.

By controlling the RF amplifier in this way, the trailing edge of the ideal CW waveform generated by the digital signal processing device with few key clicks is also emitted, and when the RF amplifier is turned off, noise generated before the RF amplifier and No spurious is output.

[Effect of the Invention] According to the keying circuit of the present invention, it is possible to obtain the effect that noise or spurious generated before the RF amplifier is keyed to the RF amplifier by the intermittent information of the electronic key and is not output when the electronic key is off.

[Brief description of drawings]

FIG. 1 is a block diagram showing a keying circuit according to an embodiment of the present invention, FIGS. 2 (a), (b) and (c) are time charts of signals in the same embodiment, and FIG. 3 is a conventional keying circuit. It is a block diagram shown. 1 ... Electric key, 2 ... Digital signal processing device, 3 ... Mixer, 4 ... Local oscillator, 5, 6, 7 ... RF amplifier, 8
...... Timing circuit.

Claims (1)

[Scope of utility model registration request] 1. A transmitter or a transceiver for converting a CW signal generated by using a digital signal processing device into a frequency used for communication and transmitting the frequency information, by supplying the digital signal processing device with interruption information of a key. A corresponding CW code is generated, and an amplification unit that amplifies the signal of the converted frequency is activated at the rising edge that generates the CW code of the interruption information of the electronic key, and the timing is shifted from the falling edge of the interruption information. A keying circuit characterized by being configured to be inactivated by a signal.