# US 2013/0278304 A1 · Apparatuses and Methods for Conversion of Radio Frequency (RF) Signals to Intermediate Frequency (IF) Signals

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- Number: US 2013/0278304 A1
- Document ID: US20130278304A1
- Status: Published application
- Kind: A1
- Application number: 13/596,016
- Filed: 2012-08-27
- Published: 2013-10-24
- Earliest claimed: 2012-04-23
- Assignees: Entropic Communications, Inc.
- Inventors: Jeremy Goldblatt; Branislav Petrovic; Martin Alderton; Wing Fat Andy Lau
- Web page: https://patentgrep.com/patent/US20130278304A1

## CPC

- H03K 21/02: Input circuits
- H03B 19/00: Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source (transference of modulation from one carrier to another H03D7/00)
- H04B 1/0053: {with common antenna for more than one band}
- H04B 1/0075: {using different intermediate frequencied for the different bands}
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- 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)
- H04B: TRANSMISSION

## Abstract

Various embodiments implement apparatuses and methods for conversion of radio frequency (RF) signals to intermediate frequency (IF) signals. More particularly, some embodiments are directed toward down conversion of RF signals to IF signals in a multi-band radio receiver, such as a satellite receiver, using a single oscillator for different frequency bands. For example, some of the apparatuses and methods presented are suitable for integration into monolithic RF integrated circuits in low-cost satellite receivers for home entertainment use.

## Claims

### Claim 1

An apparatus for conversion of radio frequency (RF) signals in a plurality of frequency bands to intermediate frequency (IF) signals, comprising:
an oscillator capable of generating an oscillator frequency LO;
a down conversion chain, comprising:
a first-stage mixer coupled to the oscillator and configured to down convert a received RF signal RF1, using the oscillator frequency LO to generate a first-stage IF signal IFa,
a first frequency divider coupled to the oscillator and configured to generate a first divided oscillation frequency by dividing the oscillator frequency LO,
a first second-stage mixer coupled to the first frequency divider and the first-stage mixer and configured to down convert the first-stage IF signal IFa using the first divided oscillation frequency to generate a first second-stage IF signal IF1,
a second frequency divider coupled to the oscillator and configured to generate a second divided oscillation frequency by dividing the oscillator frequency LO, and
a second second-stage mixer coupled to the second frequency divider and the first-stage mixer and configured to down convert the first-stage IF signal IFa using the second divided oscillation frequency to generate a second second-stage IF signal IF2.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the received RF signal RF1 is from a first frequency band and the received RF signal RF2 is from a second frequency band.

### Claim 3 (depends on 1)

The apparatus of claim 1, further comprising a first-stage filter coupled between the first-stage mixer and the first second-stage mixer and configured to filter the first-stage IF signal IFa received by the first second-stage mixer.

### Claim 4 (depends on 1)

The apparatus of claim 1, further comprising a first-stage filter coupled between the first-stage mixer and the second second-stage mixer and configured to filter the first-stage IF signal IFa received by the first second-stage mixer.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the first second-stage IF signal IF1 and the second second-stage IF signal IF2 are within substantially the same frequency band (IF1IF2).

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the first frequency divider is configured to generate the first divided oscillation frequency by dividing the oscillator frequency LO by a fraction P, and the second frequency divider is configured to generate a second divided oscillation frequency by dividing the oscillator frequency LO by a fraction Q, and P, Q, and LO are selected such that |LO/P−|LO−RF1|||LO/Q−|LO−RF2||IF1IF2.

### Claim 7

An apparatus for conversion of radio frequency (RF) signals in a plurality of frequency bands to intermediate frequency (IF) signals, comprising:
an oscillator capable of generating an oscillator frequency LO;
a first down conversion chain, comprising:
a first first-stage mixer coupled to the oscillator and configured to down convert a received RF signal RF1 using the oscillator frequency LO to generate a first first-stage IF signal IFa,
a first frequency divider coupled to the oscillator and configured to generate a first divided oscillation frequency by dividing the oscillator frequency LO, and
a first second-stage mixer coupled to the first frequency divider and configured to down convert the first first-stage IF signal IFa using the second divided oscillation frequency to generate a first second-stage IF signal IF1 using the first divided oscillation frequency; and
a second down conversion chain, comprising:
a second first-stage mixer coupled to the oscillator and configured to down convert a received RF signal RF2 using the oscillator frequency LO, to generate a second first-stage IF signal IFb,
a second frequency divider coupled to the oscillator and configured to generate a second divided oscillation frequency by dividing the oscillator frequency LO, and
a second second-stage mixer coupled to the second frequency divider and configured to down convert the second first-stage IF signal IFb using the second divided oscillation frequency to generate a second second-stage IF signal IF2.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein the received RF signal RF1 is from a first frequency band and the received RF signal RF2 is from a second frequency band.

### Claim 9 (depends on 7)

The apparatus of claim 7, further comprising a first first-stage filter coupled between the first first-stage mixer and the first second-stage mixer and configured to filter the first first-stage IF signal IFa received by the first second-stage mixer; and

### Claim 10 (depends on 7)

The apparatus of claim 7, further comprising a second first-stage filter coupled between the second first-stage mixer and the second second-stage mixer and configured to filter the second first-stage IF signal IFb received by the second second-stage mixer.

### Claim 11 (depends on 7)

The apparatus of claim 7, wherein the first second-stage IF signal IF1 and the second second-stage IF signal IF2 are within substantially the same frequency band (IF1IF2).

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein the first frequency divider is configured to generate the first divided oscillation frequency by dividing the oscillator frequency LO by a fraction P, and the second frequency divider is configured to generate a second divided oscillation frequency by dividing the oscillator frequency LO by a fraction Q, and P, Q, and LO are selected such that |LO/P−|LO−RF1|||LO/Q−|LO−RF2||IF1 IF2.

### Claim 13

A method of converting radio frequency (RF) signals in a plurality of frequency bands to intermediate frequency (IF) signals in a multi-band receiver, comprising:
providing an oscillator frequency LO using an oscillator;
down converting a received RF signal RF using the oscillator frequency LO to generate a set of first-stage IF signals IF1P;
dividing the oscillator frequency by a plurality of predetermined numbers to generate a plurality of divided oscillation frequencies; and
down converting the plurality of first-stage IF signals IF1P using the plurality of divided oscillation frequencies to generate a plurality of second-stage IF signals IF2P, respectively.

### Claim 14 (depends on 13)

The method of claim 13, wherein the plurality of first-stage IF signals IF1P and the plurality of second-stage IF signals IF2P are within substantially the same frequency band.

### Claim 15 (depends on 13)

The method of claim 13, wherein the received RF signal RF is from a first frequency band.

### Claim 16

A method, comprising:
of designing an apparatus for converting radio frequency (RF) signals in a plurality of frequency bands to intermediate frequency (IF) signals, comprising:
receiving a frequency value RFreq corresponding to an input RF signal RF for a receiver;
receiving a set of frequencies values IFreq={IFreq1, IFreq2, . . . IFreqi} such that IFreq1 IFreq2 {tilde over (□)}IFreqi, wherein the frequency value IFreqi respectively corresponds to an output IF signal IFi in a set of output IF signals IF={IF1, IF2, . . . IFi} for the receiver, and the frequency values in the set of frequency values IFreq are within substantially the same frequency band;
determining an oscillator frequency LO and a set of divisors D={D1, D2, D3, . . . Di}, such that |LO/D1−|LO−RF|||LO/D2−|LO−RF||{tilde over (□)}|LO/D1−|LO−RF||IFreq1 IFreq2 {tilde over (□)}IFreqi, wherein the fraction value Di respectively corresponds to a frequency divider in a set of frequency dividers Div={Div1, Div2, . . . Divi} included in the receiver;
providing an oscillator for the receiver configured to generate the oscillator frequency LO,
providing a first-stage mixer for the receiver configured to down convert the input RF signal RF using the oscillator frequency LO to generate a first-stage IF signal IFa,
providing the set of frequency dividers Div for the receiver, wherein frequency divider Divi is configured to generate a divided oscillation frequency DLOi in a set of divided oscillation frequencies DLO={DLO1, DLO2, DLO3, . . . DLO i} by dividing the oscillator frequency LO by the fraction Di, and
providing a set of second-stage mixers Mix={Mix1, Mix2, . . . Mixi} for the receiver, wherein second-stage mixer Mixi is configured to down convert the first-stage IF signal IFa using divided oscillation frequency DLOi in the set of divided oscillation frequencies DLO to generate the output IF signal IFi.