Abstract: A satellite IRD (Integrated Receiver Decoder) complies with DiSEqC protocol and is capable of receiving a program of a specific channel from a single cable interface device through a cable. The DiSEqC transmitter transmits a first command corresponding to the specific channel to the single cable interface device through the I/O interface and the cable. The DiSEqC receiver acquires a second command transmitted on the cable through the I/O interface in response to the DiSEqC transmitter transmitting the first command. The detecting circuit compares the second command with the first command to generate a comparison result. The DiSEqC receiver monitors the I/O interface in response to the comparison result indicating that the first command and the second command are different to determine whether there is a command other than the first command transmitted on the cable.

Abstract: A satellite IRD (Integrated Receiver Decoder) complies with DiSEqC protocol and is capable of receiving a program of a specific channel from a single cable interface device through a cable. The DiSEqC transmitter transmits a first command corresponding to the specific channel to the single cable interface device through the I/O interface and the cable. The DiSEqC receiver acquires a second command transmitted on the cable through the I/O interface in response to the DiSEqC transmitter transmitting the first command. The detecting circuit compares the second command with the first command to generate a comparison result. The DiSEqC receiver monitors the I/O interface in response to the comparison result indicating that the first command and the second command are different to determine whether there is a command other than the first command transmitted on the cable.

Abstract: A broadband dipole array antenna adopted for use in radio transmission includes a feed network, radiation units and a reflection plate. The antenna is held vertically in a trough of the reflection plate, which reflects the radiation signals of the antenna to enhance antenna directionality. The antenna and the reflection plate are fastened with adhesive tape or a Velcro strip in the trough to facilitate assembly of the antenna.

Abstract: A broadband symmetrical dipole array antenna adopted for use in radio transmission includes a symmetrical feed network, symmetrical radiation units and a reflection plate. The symmetrical feed network and the symmetrical radiation units form an antenna field of a narrower radiation angle range. The reflection plate is spaced from one side of the antenna in a parallel fashion at a selected distance to reflect the radiation signals and enhance antenna directionality.