There is provided fiber-coaxial amplifier device (10) comprising at least one output (14) and a test point (26) associated with the at least one output (14), wherein alternative first and second electrical paths (36, 38) are connectable to the at least one output (14), the first path (36) connectable to the at least one output (14) whilst bypassing the test point, the second path (38) connectable to both the at least one output (14) and the test point (26), and a relay (30) operable to connect one of the first path or the second path to the at least one output (14). The fiber-coaxial amplifier device (10) is configured for signals complying with Extended Spectrum DOCSIS.

A network element of a cable television network includes at least a first and a second upstream amplifier stage, a first attenuator and a first equalizer between the first and the second amplifier stage, and a second attenuator after the second upstream amplifier stage in upstream signal path direction. A target value is determined for total attenuation of the components of the amplifier. The total attenuation is a sum of attenuations of the first attenuator, the first equalizer, and the second attenuator. The attenuation of the first equalizer is preset. The attenuation of the first attenuator is set to a maximum value such the sum of the attenuations of the first attenuator and the first equalizer is below a first threshold value. The attenuation of the second attenuator is set such that the total attenuation reaches the target value.

A cable network system for bidirectionally communicating signals at an enhanced duplex frequency range, which may be between about 5 MHz and about 650 MHz. This system may include a first amplifier, which may be configured to condition an upstream signal proceeding from a subscriber premises to a headend, without necessarily conditioning a downstream signal proceeding from the headend to the subscriber premises, a second amplifier, which may be configured to condition the downstream signal without necessarily conditioning the upstream signal, and a shaping circuit, which may condition the upstream and downstream signals. This system also may simultaneously, or in an overlapping or offset manner, communicate signals at a full duplex frequency range without a diplex filter.

A half duplex amplifier for a cable network.

A network element of a cable television network includes at least a first and a second upstream amplifier stage, a first attenuator and a first equalizer between the first and the second amplifier stage, and a second attenuator after the second upstream amplifier stage in upstream signal path direction. A target value is determined for total attenuation of the components of the amplifier. The total attenuation is a sum of attenuations of the first attenuator, the first equalizer, and the second attenuator. The attenuation of the first equalizer is preset. The attenuation of the first attenuator is set to a maximum value such the sum of the attenuations of the first attenuator and the first equalizer is below a first threshold value. The attenuation of the second attenuator is set such that the total attenuation reaches the target value.

For broadband data communication, a data signal voltage at a signal input node can be converted to an output signal current at a signal output node. A first transistor device can contribute to the output signal current, with its transconductance or other gain reduced to accommodate larger signal swings, at which a second transistor can turn on and increase an effective resistance value of at least a portion of a gain degeneration resistor associated with the first transistor device. The second transistor can also contribute to the output signal current to help maintain or enhance an overall gain between the signal input node and the signal output node. Multiple secondary stages, push-pull arrangements, buffer amplifier configurations (which may or may not contribute to current in the gain degeneration resistor), input and output transformers, negative feedback to help reduce component variability, and frequency modification circuits or components are also described.

A network element of a cable television (CATV) network, said network element comprising one or more amplifier units for amplifying downstream signal transmission for digital output into one or more output channels; means for detecting output power of all active digital output channels; means for providing a predetermined correlation between the detected output power of said active digital output channels and a corresponding minimum bias current for said one or more amplifier units; and means for adjusting the bias current of said one or more amplifier units on the basis of the predetermined correlation.

A network interface device includes a passive path between an entry port and a first port. The network interface device also includes an active path between the entry port and a second port. The network interface device also includes a buffer in the active path configured to absorb, attenuate, terminate, or isolate radio-frequency (RF) signals. The network interface device also includes a switching element in the active path configured to cause the RF signals to bypass the buffer when the network interface is in a first state that exists during powered operation of the network interface device, and direct the RF signals to the buffer when the network interface device is in a second state that exists during non-powered operation or faulted operation of the network interface device.

An amplification system which includes a source of electrical audio signals, a first amplifier, a second amplifier, a plurality of loudspeakers, and a first phase of the first amplifier and a second phase of the second amplifier reproduced in parallel having a time delay between first and second phase amplification for out of phase correction. The time delay is configured to correct poor sound signals while amplifying weaker harmonics and sound signals of different frequencies, thereby adjusting sound output of the amplification system and acoustical characteristics of a room. The amplification system is useful for providing improved sound quality and increased audio efficiencies.

There is provided an amplifier device comprising a first directional coupler (12: 30, 32) and a second directional coupler (14: 30′, 32′) connected together so as to create separate upstream (16) and downstream (18) paths in which amplifier means (24, 24′) are located, wherein the first and second directional couplers (12, 14: 30, 32; 30′, 32′) are configured to have different signal loss characteristics, one of the directional couplers having low signal loss characteristics for upstream signals and the other directional coupler having low signal loss characteristics for downstream signals. The signal loss characteristics are preferably the coupling loss of each directional coupler (12, 14: 30, 32; 30′, 32′). The first and second directional couplers may each comprise a microstrip directional coupler (30; 30′) connected to a ferrite directional coupler (50; 50′).