Automotive

Remote Keyless Entry (RKE) systems

Remote Keyless Entry (RKE) systems consist of a key fob transmitter and a receiver inside the vehicle. Frequencies used are 315MHz in the U.S. and Japan, and 433.92MHz / 868MHz in Europe.

RKE Systems:

• Lock and unlock the doors (and trunk).
• Alarm the vehicle against theft.
• New systems include remote start and advanced car finder functions.

RKE Market Growth Factors:

• It is estimated that 60 Million automobiles will be sold worldwide in 2004.
• RKE is now a standard feature in most new cars.
• About 60% of cars worldwide are sold with RKE installed.
• About 80% of cars in the North American market are sold with RKE installed.
• RKE systems are also a high volume after-market accessory.
• RKE systems provide enhanced security and serve as an effective safeguard against auto theft.

Wireless World AG offers the followingproducts from RF Monolithics, Inc. for RKE Systems:

• SAW Resonators for transmitters & receiver local oscillators.
• Coupled Resonator Filters for RF Receiver circuit.
• Virtual Wire RF Transmitters for complete RF Transmitter circuit.
• Virtual Wire RF Receivers for complete RF Receiver circuit.
• Virtual Wire RF Transceivers for 2-way systems.

Feature Requirements for RKE Design:

• Low power consumption in both the RKE transmitter and receiver.
• Excellent range.
• High Reliability.
• Low cost.
• Wide range of frequencies: 300Mhz – 1000 MHz.
• Rugged Design.

Technology for RKE Design:
RKE can be designed using Surface Acoustic Wave (SAW) or Phase Lock Loop (PLL) technology.
SAW design has the following advantages over PLL:

• SAW-based RKE designs are inherently simple and low current.
• Battery life of a SAW device is longer compared to a PLL design.
• SAW-based designs exhibit low phase noise and harmonics, and are easily certified to all major radio regulations.
• SAW devices tolerate extremes of temperature and shock.

Summary:
The Remote Keyless Entry market will continue to grow with rising automobile sales.
SAW-based solutions are small in size, simple in design and provide the lowest power consumption to promote longer battery life for RKE systems.

Tire Pressure Monitoring (TPM) systems

Facts:
27% of passenger cars and 33% of light trucks are driven with one or more substantially under inflated tires. An estimated 23,000 crashes and 535 fatal crashes annually involve blowouts or flat tires.
- National Highway Traffic Safety Administration (NHTSA)
It is estimated that 83% of tire pressure loss occurs gradually – often without being noticed by the driver.
- General Motors
Running tires at 20% under-inflation can reduce tire life by upto 50%.
- Goodyear & Michelin
Fuel Efficiency is reduced by one percent for every 3 psi of under inflation.
- Goodyear

These figures strongly highlight the need for a robust mechanism to detect loss of tire pressure early, thus enabling timely rectification leading to enhanced safety.
Tire Pressure Monitoring (TPM) acts as an early warning to monitor tire pressure and temperature.

TPM Systems:

• Reduce risk of damage to tires.
• Significantly increase the life of a tire.
• Maximize handling and braking.
• Increase fuel economy.
• Save lives.

US Legislation – TREAD Act:

• Mandates installation of TPM Systems that warn the driver when a tire is significantly under-inflated.
• Applies to passenger cars, trucks, multipurpose passenger vehicles, and buses with a gross vehicle weight rating of 10,000 pounds or less, except vehicles with dual wheels on an axle.
• Either Direct or Indirect systems can be used for short-term (Between November 1, 2003, and October 31, 2006).

Phase in schedule:
- Nov 1, 2003 to Oct 31, 2004 : 10% min compliance
- Nov 1, 2004 to Oct 31, 2005 : 35% min compliance
- Nov 1, 2005 to Oct 31, 2006 : 65% min compliance

Final rule will be issued by March 1, 2005 (to establish performance requirements needed after November 1, 2006).
- Source: National Highway Traffic Safety Administration

TREAD Act – Update:
* U.S. Court of Appeals for the 2nd Circuit found the TPM rules “contrary to law and arbitrary and capricious,” and sent it back to the National Highway Traffic Safety Administration (NHTSA) for further rulemaking proceedings and ordered the rewrite of TPM rules that allow automakers to install ineffective (Indirect) TPM Systems.
* The NHTSA sent letters to auto makers and tire manufacturers asking them to detail their progress on installing TPM Systems and responses were due October 17, 2003.

Direct vs. Indirect Systems:
*Direct Systems:
Wireless sensor in or on(*) each tire that monitors air pressure and temperature separately and communicates the measurements from inside the tire to a central receiver module.
* Indirect Systems:
No sensor in any tires. Directly ties in to the vehicle’s antilock braking system (ABS) and monitors rotation of tires, not actual air pressure. No way to monitor temperature.
(*) Some systems have sensors that mount on the valve stem.
* NHTSA found that Direct TPM systems were better able to detect under-inflation, had more consistent warning thresholds, and were quicker to provide warnings than the Indirect TPM systems.

Direct System	Indirect System
Alerts when any or all tires drop in pressure.	Alerts only when any single tire loses pressure.
Indicates to driver which tire is low.	Won’t indicate to driver which tire is low.
Instant alert, when pressure drops below preset level.	No alert if all tires are losing pressure over time or at the same rate.
Heavy load does not affect alert.	Won’t alert in time to prevent tire damage especially if heavily loaded.
Alerts when pressure drops 25%. Can also provide incremental pressure measurements.	Alerts only when pressure drops >30%.

TPM Market Growth Factors:

• Cost Savings brought forth by significant increase in the life of a tire and increased fuel economy.
• Improved Safety.
• US market fueled by the TREAD Act.
• European Union may enact similar legislation.
• Japanese and Asian consumer and commercial automotive industry markets are experiencing growing awareness on importance of tire safety.

Market Size (worldwide):
2004: 8 million TPM systems
2005: 15 million TPM systems
2006: 25 million TPM systems
2007: 42 million TPM systems
2008: 48 million TPM systems.

Direct RF TPM System Components:

• Inside the tire: TPM Sensor, mounted on rim or valve stem; consists of pressure/temperature sensor, encoder and RF transmitter circuit. Battery powered.
• Onboard the car: TPM receiver unit, decoder and information display.

NB: In some systems, the TPM and RKE functions are integrated into one receiver in the car.

Wireless World AG is providing the followingRF Monolithics products for TPM Systems:

• SAW Resonators for transmitters & receiver local oscillators.
• Coupled Resonator Filters for RF Receiver circuit.
• Virtual Wire RF Transmitters for complete RF Transmitter circuit.
• Virtual Wire RF Receivers for complete RF Receiver circuit.
• Virtual Wire RF Transceivers for 2-way systems and further integration with RKE, security, garage door openers, etc.

ASK, OOK, FSK:

• ASK (Amplitude Shift Keyed) and OOK (On-Off Keyed) are the major technologies in which RFM participates.
• FSK (Frequency Shift Keyed) is an alternate modulation technology used in TPM systems. For FSK systems, RFM can provide Coupled Resonator Filters on the receive side.
• Typical TPM data rates (4800-9600 bps) can be achieved with ASK, OOK and FSK systems.

Advantages of ASK vs. FSK in TPM:

• ASK can be implemented on a lower current budget than FSK, reducing battery size and cost.
• ASK transmitter designs can avoid the need for fragile crystals.
• ASK systems can be designed with no production adjustments and are tolerant of small component drifts due to aging, etc.
• Well-designed ASK systems require only a 1 to 8 dB power margin to “capture” a channel from an in-band interfering signal. This provides better “real world” interference rejection than FSK in many circumstances.

Advantages of SAW vs. PLL in TPM:

• SAW-based TPM designs are inherently simple and low current.
• Battery life of a SAW device is longer compared to a PLL design.
• SAW-based designs exhibit low phase noise and harmonics, and are easily certified to all major radio regulations.
• SAW devices tolerate extremes of temperature and shock found in TPM applications.

Summary:

• Growing need for improved driving safety, reliability, performance, fuel-efficiency and government regulations fuel the TPM market.
• The Direct TPM systems comprising of the wireless solution is clearly proven to be more accurate and effective than the Indirect TPM systems.
• SAW-based solutions are small in size, simple in design and provide the lowest power consumption to promote longer battery life.
• RF Monolithics, Inc. is the dominant supplier of SAW products for the Tire Pressure Monitoring market.