Abstract: A frequency synthesizer using a fixed oscillator driving a comb line generator to generate a spectrum of comb lines, one of which is selected by a switched array of fixed-tuned, YIG passband filters. The selected comb line is combined in a mixer with a signal from a local oscillator, which, preferably, is a direct digital synthesizer. The output of the mixer is fed to another switched array of fixed-tuned YIG passband filters where only the desired sideband is selected and the comb line and the other sideband is filtered out. In various alternative embodiments, tunable YIG filters are substituted for each array. Some embodiments also use a reverse slope equalizer to break up the coherent energy in the comb line spectrum at the output of the comb line generator to allow RF amplification to be applied without saturating the amplifier.

Abstract: A hub circuit with an integrated bridge circuit carried out in software including a switch for bypassing the bridge process such that the two bridged networks effectively become one network. An in-band management process in software is disclosed which receives and executes network management commands received as data packets from the LANs coupled to the integrated hub/bridge. Also disclosed is hardware and software to implement an isolate mode where data packets which would ordinarily be transferred by the bridge process are not transferred except in-band management packets are transferred to the in-band management process regardless of which network from which they arrived. An out-of-band to in-band management process receives network management commands and executes them or forwards them in-band to whatever device to which they are addressed.

Abstract: A method of making a semiconductor memory is disclosed. The cell has MNOS structure, and comprises a p-type silicon substrate 27 with n.sub.+ type layers 21, 23, a silicon dioxide film 19 thereon, a reduced pressure SiN film 17 thereon and a polysilicon film 14 thereon. The surface of the channel region 25 has projecting portions so the semiconductor memory employing the cell, compared to that of the prior art, permits tunneling of electrons with a low programming voltage.

Abstract: A personal bar code scanning device for aiding shoppers in keeping track of their expenditures and speeding the process of check-out and taking advantage of coupons. A microprocessor coupled to a bar code reader, a communication port, an audible feedback device and a touchscreen or light pen and display combination carrys out bar code scanning in a store as a shopper shops. The user selects a shopping list from a collection of one or more shopping lists or creates a new list from a database or by spelling out the items to purchase on a keyboard. The user then downloads the store's current price list by modem or by connecting to the store computer when the store is entered. When the shopper wishes to purchase an item, the personal bar code scanning device is placed adjacent to the bar code on the package of the item and the user presses a button to scan the bar code.

Abstract: A low phase noise third order phase lock loop which can track and eliminate microphonic disturbances and phase hits. The PLL utilizes a third order loop filter which incorporates two integrators. These two integrators, when coupled with the integration which occurs at the voltage control input of the voltage controlled oscillator within the PLL yield an open loop transfer function with a --18 dB/octave rolloff over a band of frequencies which at least encompasses the spectral content of the microphonic or phase hit phase noise disturbance to be eliminated. The open loop gain of the phase lock loop must be set high enough such that the phase lock loop does not oscillate and such that the loop converges and locks. The integrators are implemented with operational amplifiers with RC feedback networks. The values of the components in the RC feedback networks set the frequencies of two zeroes in the transfer function.