JPH1117628A - On-vehicle electronic controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a high-frequency receiver from deteriorating in S/N by setting an operation clack frequency, so as not to make the operation clock frequency and the frequency of the multiple to be present inside the broadcasting band of the high-frequency receiver. SOLUTION: A CPU requires clocks for an operation so as to synchronize an arithmetic processing, a ROM and a RAM, an oscillation circuit 12 is provided on the outside of the CPU, and clock signals are supplied to the CPU, the ROM and the RAM. Then frequencies pertinent to the fundamental wave component of the clock signals and the multiple of fundamental waves match the reception frequency band of the high-frequency receiver present inside the same vehicle, they are injected to the receivers as clock noise signals. Thus, setting is performed so as to make the frequencies equivalent to the fundamental wave of the operation clock frequency of this electronic control, and the multiples of the fundamental waves avoid the respective frequency bands of the high-frequency receiver present inside the same vehicle compartment. Thus, the need for noise investigation normally performed by the electronic controller is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an electronic control unit for a vehicle, wherein the clock noise for CPU control is AM, FM, TV,
The present invention relates to an in-vehicle electronic control device that does not affect the reception performance of a plurality of high-frequency receivers such as a keyless tuner.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 63-39174 discloses an operation clock frequency of an electronic control unit for ensuring the reception sensitivity of a high-frequency receiver. 8 which is the bandwidth of the broadcast band
There is a technique for suppressing reception interference due to beat noise in the AM band by separating the signal by KHz or more.

[0003]

In the prior art, when the operating clock frequency of the on-vehicle electronic control device and its multiplied frequency exist in the broadcast band of the high frequency receiver, it becomes a carrier wave in the reception frequency band of the high frequency receiver. It becomes noise (carrier noise).

Since this noise affects various high-frequency receivers, a filter for suppressing noise is inserted between a power supply and GND in the control device so that a noise component of a clock frequency is suppressed on the electronic control device side. Noise was suppressed by taking measures such as devising the pattern of the internal printed circuit board of the electronic control unit.

In this method, it is necessary to consider the above-mentioned noise countermeasures every time a pattern of a printed circuit board is designed.
Repeated pattern changes and examinations were required.

[0006]

The above problem can be avoided by setting the operating clock frequency so that the operating clock frequency of the on-vehicle electronic control device and its multiplied frequency do not exist in the broadcasting band of the high frequency receiver. .

[0007] By setting the operating clock frequency of the on-vehicle electronic control device and its multiplied frequency so as to be out of the broadcasting band of the high frequency receiver set in the same vehicle, it is possible to avoid the reception interference of the high frequency receiver. I can do it.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. The CPU 1 performs digital processing of various data required for the electronic control unit. The RAM 4 is a readable and writable storage element.

An I / O is connected to a CPU and a RAM via a bus 1-a.
Is connected to

The CPU fetches external SW information via the I / O, and controls the R based on a control signal input from the high frequency receiver.
According to a program stored in the OM, digital processing of various signals is performed to control an external wireless actuator and various actuators.

The CPU requires an operating clock to perform arithmetic processing and synchronize with the ROM and RAM. In FIG. 1, an oscillation circuit 12 is provided outside the CPU, and a clock signal is output from the CPU.
It is supplied to PU, ROM and RAM.

In recent years, the operating speed of the CPU has been increased, and the operating clock of the CPU must be increased accordingly. However, the fundamental wave component of the clock signal and the frequency corresponding to the multiplication of the fundamental wave exist in the same vehicle. When the received frequency band coincides with the receiving frequency band of the high-frequency receiver, the signal is injected into the corresponding receiver as a clock noise signal.

FIG. 2 shows that the clock noise of the electronic control device propagates in the air as radio waves from the power supply line, ground line, various signal lines, and control signal lines of the electronic control device, and is injected as a clock noise signal from the antenna of various high-frequency receivers. This is shown.

FIG. 3 shows how clock noise in the electronic control unit is injected from the power supply line and the GND line of the high frequency receiver via the power supply line and the GND line of the electronic control unit.

If the frequency of the noise injected as described above overlaps with the reception frequency band of the high-frequency receiver, it becomes noise when a normal signal of this frequency is received, and S / N
This will lead to a worsening of the ratio.

FIG. 4 shows an example in which only an AM band receiver is present in the cabin. Domestic AM band is 522kHz to 1629KH
Therefore, if a clock signal of, for example, 1000 kHz exists in this band because of the frequency z, then (4-a) 100 in the AM band
The noise component at 0 KHz increases, resulting in 1000 KH
The S / N ratio of z deteriorates. To prevent this, the clock frequency is shifted from the AM broadcast band (4-b: 2000KH
z), it is possible to prevent an adverse effect on the AM band reception performance.

FIG. 5 shows an example in which an AM band receiver and an FM receiver are present in the cabin. Domestic FM broadcast band is 76-90MHZ
z, the clock frequency in the electronic control unit is 20M
Hz, 20 MHz which is a fundamental wave and 40 MHz, 60 MHz, 80 MHz and 100 which are multiples of the fundamental wave.
80MHz in the FM band
The S / N ratio of Hz will be degraded.

This can be prevented by setting the clock frequency to, for example, 50 MHz (5-b).
50 MHz and the frequency of this multiplication are 50, 100, 15
0... MHz does not exist in the FM frequency band.

FIG. 6 shows an example in which an AM band receiver, an FM band receiver, and a TV band (VHF band) receiver are present in the vehicle interior. T
V band frequency is 90-108MHz, 170-222MH
Since it is z, it can be realized by setting the clock frequency to 75 MHz or 150 MHz, for example, to avoid this band and the FM band.

As described above, the fundamental wave of the operating clock frequency of the electronic control device and the frequency corresponding to the multiplication of the fundamental wave are:
By setting so as to avoid each frequency band of the high-frequency receiver existing in the same vehicle interior, it is possible to prevent the S / N ratio of the high-frequency receiver from deteriorating.

[0021]

According to the present invention, there is an effect that it is not necessary to carry out the noise examination normally performed in the electronic control unit.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a state of injection of a clock noise signal into the electronic control device.

FIG. 3 is an explanatory diagram of a state of injection of a clock noise signal into the electronic control device.

FIG. 4 is an explanatory diagram of clock noise of an AM band receiver.

FIG. 5 is an explanatory diagram of clock noise when an AM band and an FM band exist.

FIG. 6 is an explanatory diagram of clock noise when an AM band, an FM band, and a TV band exist.

[Explanation of symbols]

 12: clock oscillation circuit, 4-a: domestic FM broadcast band.

Claims (2)

[Claims] 1. An I / O (Imput / Output) that includes a CPU that receives various signals mounted on a vehicle and performs arithmetic processing based on the signals, and outputs a result calculated by the CPU as a control signal;
A read-only ROM that stores a control program for the above calculation, a control program constant, a RAM and a CPU that can write and read data required for the calculation.
In the electronic control device provided with the clock oscillation circuit for the operation clock of the above, the fundamental frequency of the oscillation frequency of the operation clock and the frequency corresponding to the multiplication thereof are set in the same vehicle.
By setting it so that it does not exist within the used center frequency and frequency bandwidth of the high frequency receiver for the M, FM or TV broadcasting band, the reception of the high frequency receiver for the AM, FM or TV broadcasting band set in the same vehicle is performed. An in-vehicle electronic control device characterized by preventing a decrease in performance. 2. The high frequency band according to claim 1, wherein the high frequency band is 250 MHz.
z, AM, FM or T within this band
An on-vehicle electronic control device for preventing deterioration of reception performance of a V broadcast band.