The present specification describes a system. The system includes a code generator to 1) generate a Morse code message from an intended message and 2) decode a received Morse code message. The system also includes a high-frequency transceiver to 1) transmit Morse code messages in the high frequency electromagnetic range and 2) receive Morse code messages in the high frequency electromagnetic range.

The present specification describes a system. The system includes a code generator to 1) generate a Morse code message from an intended message and 2) decode a received Morse code message. The system also includes a high-frequency transceiver to 1) transmit Morse code messages in the high frequency electromagnetic range and 2) receive Morse code messages in the high frequency electromagnetic range.

A Morse code input method and a portable electronic device for performing the method are provided. The portable electronic device includes a processing circuit and a touchscreen. The method includes: sensing touch events by the touchscreen, recording and comparing time periods of the touch events by the processing circuit; identifying, by the processing circuit, inputs in the ith touch event through (k1)th touch event as short signals when the time period of the kth touch event is greater than or equal to N times the time period of (k1)th touch event and the kth touch event is not the last touch event, wherein N is a positive number, k and i are positive integers, with k being greater than or equal to i, and the ith touch event is the earliest one of the touch events in which inputs have not yet been identified as long or short signals.

A Morse code input method and a portable electronic device for performing the method are provided. The portable electronic device includes a processing circuit and a touchscreen. The method includes: sensing touch events by the touchscreen, recording and comparing time periods of the touch events by the processing circuit; identifying, by the processing circuit, inputs in the ith touch event through (k1)th touch event as short signals when the time period of the kth touch event is greater than or equal to N times the time period of (k1)th touch event and the kth touch event is not the last touch event, wherein N is a positive number, k and i are positive integers, with k being greater than or equal to i, and the ith touch event is the earliest one of the touch events in which inputs have not yet been identified as long or short signals.

A Morse code input method and a portable electronic device for performing the method are provided. The portable electronic device includes a processing circuit and a touchscreen. The method includes: sensing touch events by the touchscreen, recording and comparing time periods of the touch events by the processing circuit; identifying, by the processing circuit, inputs in the ith touch event through (k-1)th touch event as short signals when the time period of the kth touch event is greater than or equal to N times the time period of (k-1)th touch event and the kth touch event is not the last touch event, wherein N is a positive number, k and i are positive integers, with k being greater than or equal to i, and the ith touch event is the earliest one of the touch events in which inputs have not yet been identified as long or short signals.

A Morse code input method and a portable electronic device for performing the method are provided. The portable electronic device includes a processing circuit and a touchscreen. The method includes: sensing touch events by the touchscreen, recording and comparing time periods of the touch events by the processing circuit; identifying, by the processing circuit, inputs in the ith touch event through (k-1)th touch event as short signals when the time period of the kth touch event is greater than or equal to N times the time period of (k-1)th touch event and the kth touch event is not the last touch event, wherein N is a positive number, k and i are positive integers, with k being greater than or equal to i, and the ith touch event is the earliest one of the touch events in which inputs have not yet been identified as long or short signals.

Aspects of the present invention relate to methods, systems, and computer-readable media for triggering an identification signal broadcast of a first navigational aid equipment using a tone in the voice band transmitted by a second navigational aid equipment. Aspects include receiving, at the first navigational aid equipment, a tone in a voice band of second navigational aid equipment. Aspects also include transmitting, by the first navigational aid equipment, the identification associated with the first navigational aid equipment identification when the tone is received.

Aspects of the present invention relate to methods, systems, and computer-readable media for triggering an identification signal broadcast of a first navigational aid equipment using a tone in the voice band transmitted by a second navigational aid equipment. Aspects include receiving, at the first navigational aid equipment, a tone in a voice band of second navigational aid equipment. Aspects also include transmitting, by the first navigational aid equipment, the identification associated with the first navigational aid equipment identification when the tone is received.

One aspect is a circuit for tuning a resonance frequency of an electrically small antenna and directly exciting the electrically small antenna. The circuit includes a first source configured for providing a constant voltage. The circuit also includes an antenna and a switched capacitor configured for being alternatively alternately coupled to the first source to be charged thereby and to the antenna for exciting the antenna. Another aspect is a transmitter for transmitting a wireless signal using an antenna without using a variable voltage source to excite the antenna. The transmitter includes a first source configured for providing a constant voltage. The transmitter further includes an antenna and a switched capacitor configured for being alternately coupled to the first source to be charged thereby and to the antenna for exciting the antenna and for tuning a resonance frequency of the antenna.

One aspect is a circuit for tuning a resonance frequency of an electrically small antenna and directly exciting the electrically small antenna. The circuit includes a first source configured for providing a constant voltage. The circuit also includes an antenna and a switched capacitor configured for being alternatively alternately coupled to the first source to be charged thereby and to the antenna for exciting the antenna. Another aspect is a transmitter for transmitting a wireless signal using an antenna without using a variable voltage source to excite the antenna. The transmitter includes a first source configured for providing a constant voltage. The transmitter further includes an antenna and a switched capacitor configured for being alternately coupled to the first source to be charged thereby and to the antenna for exciting the antenna and for tuning a resonance frequency of the antenna.