Abstract: A messaging system, and method of operation thereof, which supports combinations of directory and mailing list addressing mechanisms. Intended message recipients are specified as declarative addresses, which may include combinations of directory and mailing list information. The messaging system includes a messaging server and an address resolution module. The messaging server receives a message from a sender system and transmits the message to the recipient system. The address resolution module, which is coupled to the messaging server, receives a declarative address associated with the message, resolves the declarative address into at least one messaging address and transmits the at least one messaging address to the messaging server. In one embodiment, a database system may be coupled to the address resolution module to allow address resolution based on information stored in a database.

Abstract: The present invention is a messaging system, and method of operation thereof, which provides message recipients with control over the delivery of message and charges the cost of a message to the sender of the message. A message is received at a messaging server from a sender system, the message including an indication of a recipient system. A notification message is transmitted to the recipient system, allowing the message recipient to determine whether they desire the message to be delivered. If so, an activation message is received from the recipient system and the message is transmitted to the recipient system. A charge for the message is assessed to the sender of the message. The message is stored in the messaging server until the activation message is received. At least a portion of the assessed charge may be credited or debited to the recipient of the message.

Abstract: A linear, high frequency, variable gain amplifier is disclosed. The amplifier includes a differential amplifier transistor pair for providing a gain controlled output signal in response to an input signal. Diode pairs connected between the emitters of the transistors, in conjunction with transistor gain control circuitry, provide for gain control of the output signal. A dummy amplifier connected to the differential amplifier transistor pair cancels the capacitance effects created by the diode pair.

Abstract: A feedback circuit for use with a power amplifier is disclosed. A feedback circuit includes means for providing An inactive state wherein the input for the feedback circuit comprises an output of the loop filter operational amplifier and an active state wherein the input for the feedback circuit consists of a coupled, demodulated power amplifier output. A soft switching circuit is included for gradually switching between the inactive and active states, such that transient spikes are prevented within the feedback circuitry signal.

Abstract: The present invention provides a method and apparatus for detecting and compensating for transmitter phase shift in a radio transmitter. A local oscillator generates a local oscillator signal. A modulator such as an I/Q modulator modulates input signals onto the local oscillator signal to generate a forward signal. That forward signal is amplified and otherwise prepared for transmission via an antenna. The transmitted signal is detected, and a phase adjuster substantially continuously detects and cancels undesired phase shifts in the detected signal caused by elements in the radio chain. A specific, example embodiment of the present invention is provided in a Cartesian feedback system wherein the phase of the feedback signal is detected and aligned with the phase of the original modulated signal, providing uncorrupted I and Q baseband feedback signals.

Abstract: A message storage system, for use with a communication network and in which a network presence is provided for an entity, stores a message from a sender to a network presence. The message storage system accepts a query including a specified property, and generates a mailbox including the stored message when one of the message properties is the specified property. A software agent processes the stored message in accordance with a processing preference included in attributes associated with the entity. The message storage system generates a summary of the message and updates the summary of the message in response to modifications to the message.

Abstract: A communication network system provides a network presence for an entity, the network presence being identified by handle information relating to the entity, the handle information being unrelated to a physical endpoint. Attributes of the entity are associated with the handle information. The handle is a source of vendor services to the entity, and may be a source of services from the entity to others.

Abstract: A directory system, for use with a communication network and in which a network presence is provided for an entity having attributes, stores the attributes and responds to queries. The attributes may have associated authenticity information. The attributes may have a hierarchical relationship, and the queries include information dependent on this hierarchical relationship. When the query includes attributes, the directory system provides identifying information for the entity and automatically transfers the identifying information to a vendor service. When the attributes have associated security information, the directory service responds to queries with only attribute information associated with a public security indication.

Abstract: A message delivery system, for use with a communication network and in which a network presence is provided for an entity having attributes, delivers a message from a sender to the network presence. In some cases, information identifying the sender is omitted from the message. The delivery system can append non-repudiable sender information to the message. The sender can provide selected attributes as an address, and the delivery system replaces the selected attributes with an address of the network presence without disclosing the address to the sender. A software agent processes the delivered message in accordance with a processing preference included in the entity attributes.