# US 5,352,993 A · Voltage controlled saw oscillator

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- Number: US 5,352,993 A
- Document ID: US5352993A
- Status: Granted
- Kind: A
- Application number: 07/954,509
- Filed: 1992-09-30
- Granted: 1994-10-04
- Earliest claimed: 1992-09-30
- Assignees: Telefonaktiebolaget L M Ericsson
- Inventors: Heinz B. Mader
- Web page: https://patentgrep.com/patent/US5352993A

## CPC

- H03B 5/36: active element in amplifier being semiconductor device ({H03B5/323, H03B5/326} , H03B5/38 take precedence)
- H03B 5/326: {the resonator being an acoustic wave device, e.g. SAW or BAW device}
- H03B 5/366: {and comprising means for varying the frequency by a variable voltage or current}
- H03B 2200/0058: with particular transconductance characteristics, e.g. an operational transconductance amplifier
- H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H)

## Abstract

A voltage controlled surface acoustic wave oscillator includes an integrated circuit and a two port resonator connected as a feedback element around the integrated circuit. The integrated circuit includes a phase shifting network and an amplifier directly connected to the phase shifting network.

## Claims

### Claim 1

An oscillator comprising:
an integrated circuit comprising:
a phase shifting network, and
an amplifier connected to said phase shifting network; and
a resonator having an input port and an output port connected as a feedback element around said integrated circuit, wherein said phase shifting network comprises a multiplier having an input terminal and an output terminal, a first transconductance amplifier connected in circuit to said output terminal of said multiplier, and a second transconductance amplifier and a third transconductance amplifier connected in series and in circuit in parallel to said multiplier and said first transconductance amplifier.

### Claim 2 (depends on 1)

An oscillator as recited in claim 1, wherein said resonator is a surface acoustic wave transversal coupled filter.

### Claim 3 (depends on 1)

An oscillator as recited in claim 1, wherein said amplifier has an output port, and further comprising means for connecting said output port of said amplifier to said input port of said resonator.

### Claim 4

A voltage controlled surface acoustic wave ("SAW") oscillator comprising:
an integrated circuit formed on an insulative substrate which includes
an amplifier having a pair of input terminals, an output terminal, a first signal output terminal, and a second signal output terminal,
a phase shift network having a first input, a second input and a pair of phase shifted outputs, said outputs being connected to the pair of inputs of said amplifier, and
a SAW transversal coupled filter having an input terminal, an output terminal, and a common ground terminal, said input terminal of said SAW transversal coupled filter connected to the output terminal of said amplifier, said output terminal of said transversal coupled filter connected to the second input of said phase shift network and to an inductor, and said common ground terminal connected in circuit to a point between said inductor and said first input of said phase shift network, wherein said phase shifting network comprises a multiplier having an input terminal and an output terminal, a first trans conductance amplifier connected in circuit to said output terminal of said multiplier, and a second transconductance amplifier and a third transconductance amplifier connected in series and in circuit in parallel to said multiplier and said first transconductance amplifier.

### Claim 5 (depends on 4)

A voltage controlled surface acoustic wave oscillator as recited in claim 4, comprising a second inductor connected in circuit at one point between said first inductor and said first input of said phase shift network and at a second point between said output terminal of said amplifier and said input terminal of said SAW transversal coupled filter.