Frequency adjustable surface acoustic wave oscillator

A frequency adjustable surface acoustic wave oscillator comprising:

• a piezoelectric material;
• a plurality of transmitting fingers interfacing with a first portion of the piezoelectric material, the plurality of transmitting fingers configured to initiate a surface acoustic wave on the piezoelectric material;
• a plurality of receiving fingers interfacing with a second portion of the piezoelectric material, the plurality of receiving fingers configured to receive the surface acoustic wave and generate an electrical signal;
• a plurality of phase adjustable drivers, each of the plurality of phase adjustable drivers having a driver input and a driver output, the driver output of each of the plurality of phase adjustable drivers connected to one of the plurality of transmitting fingers;
• a plurality of phase adjustable receivers, each of the plurality of phase adjustable receivers having a receiver input the receiver input connected to one of the plurality of receiving fingers;
• a common in-phase summing block having inputs and an output;
• a common phase-shifted summing block having inputs and an output;
• a receiver summing block adapted to receive the common in-phase summing block output and the common phase-shifted summing block output via a phase-shifter to produce a receiver summed output;
• each of the plurality of phase adjustable receivers further comprising:
• two adjustable gain amplifiers, the inputs of the adjustable gain amplifiers connected to one of the plurality of receiving fingers;
• the output of one adjustable gain amplifier connected to an input of the common in-phase summing block;
• the output of the other adjustable gain amplifier connected to an input of the common phase-shifted summing block;
• and
• a gain element adapted to receive the receiver summed output, the gain element having an output adapted to excite the driver inputs.

A frequency adjustable surface acoustic wave oscillator comprising:

• a piezoelectric material;
• a plurality of transmitting fingers interfacing with a first portion of the piezoelectric material, the plurality of transmitting fingers configured to initiate a surface acoustic wave on the piezoelectric material;
• a plurality of receiving fingers interfacing with a second portion of the piezoelectric material, the plurality of receiving fingers configured to receive the surface acoustic wave and generate an electrical signal;
• a plurality of phase adjustable drivers, each of the plurality of phase adjustable drivers having a driver output, the driver output of each of the plurality of phase adjustable drivers connected to one of the plurality of transmitting fingers;
• a plurality of phase adjustable receivers, each of the plurality of phase adjustable receivers having a receiver input and receiver output, the receiver input connected to one of the plurality of receiving fingers;
• a receiver summing network adapted to sum the receiver output from each of the plurality of phase adjustable receivers and produce a receiver summed output;
• a tapped delay having an input and a plurality of taps;
• each of the phase adjustable drivers further comprising:
• a summing block having inputs and an output;
• a plurality of switches, each of the plurality of switches interposed between one of the taps of the tapped delay, and one of the inputs of the summing block;
• the output of the summing block connected to the output of the phase adjustable driver;
• and
• a gain element adapted to receive the receiver summed output, the gain element having an output adapted to excite the input of the tapped delay line.

A method of implementing a frequency adjustable surface acoustic wave oscillator the method comprising:

• providing transmitting fingers and receiving fingers adapted to transmit and receive respectively surface acoustic waves on a piezoelectric surface;
• transmitting a surface acoustic wave onto the piezoelectric surface by controlling the phase of an input signal to each of the transmitting fingers;
• wherein the step of controlling the phase of an input signal to each of the transmitting fingers further comprises the steps of:
• multiplying the input signal by a first gain factor;
• multiplying a phase-shifted version of the input signal by a second gain factor;
• and
• applying the sum of the two resulting signals to a transmitting finger;
• receiving the surface acoustic wave with the receiving fingers to produce a plurality of received signals;
• adjusting the phase of each of the plurality of received signals;
• summing the phase adjusted received signals;
• and
• amplifying the summed signals to generate the input signal.

A frequency adjustable surface acoustic wave oscillator comprising:

• A piezoelectric layer deposited onto a semiconductor;
• a plurality of transmitting fingers interfacing with a first portion of the piezoelectric layer, the plurality of transmitting fingers configured to initiate a surface acoustic wave on the piezoelectric layer;
• a plurality of receiving fingers interfacing with a second portion of the piezoelectric layer, the plurality of receiving fingers configured to receive the surface acoustic wave;
• a plurality of phase adjustable drivers, each of the plurality of phase adjustable drivers further comprising:
• a summer, having a summer output and a plurality of summer inputs, the summer output connected to a corresponding one of the plurality of transmitting fingers;
• each of the plurality of summer inputs adapted to receive a phase-shifted version of a driver input via a transmitter switch.
• a plurality of receiver busses;
• a receiver summing system adapted to form a phase-shifted version of each of the receiver busses and form a summed output;
• and
• a plurality of phase adjustable receivers, each of the phase adjustable receivers further comprising:
• a plurality of receiver switches having inputs and outputs, the inputs of the receiver switches connected to one receiver finger via a buffer, the output of each of the receiver switches connected to one of the plurality of receiver busses;
• a gain element adapted to receive the summed output and excite the driver input.