JPS5843311Y2 - phase matched signal oscillator - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a phase matching signal oscillator for facsimile machines and the like.

In a facsimile machine, in order to synchronize document scanning between a transmitter and a receiver, a phase matching signal corresponding to scanning is sent from the transmitter to the receiver.

Such a phase matching signal may be inserted at the center of a blanking signal that determines the effective screen width with a pulse width shorter than that of the blanking signal.

When scanning a document placed on a rotating drum by rotating the drum, the method of obtaining a blanking signal every rotation using a proximity switch is such that even if the drum rotation speed changes, the blanking signal time in one cycle is This is advantageous because the ratio does not change.

Similarly, for the phase matching signal, a separate proximity switch may be provided and the signal may be used, but providing two proximity switches requires space and is not suitable for miniaturizing the device.

If the blanking signal generation positions for transmission and reception are different in a transceiver with an integrated transmitter and receiver, four proximity switches are required, which is even more inappropriate.

To electrically obtain a phase-matched signal, conventionally two timers are required, one for delay and one for determining pulse width.

That is, a timer that starts the phase matching signal later than the start time of the blanking signal, and a timer that determines the pulse width of the phase matching signal are required.

However, in this method, the rotational speed of the drum is limited to one speed, and if the drum rotational speed is to be increased to multiple speeds, a large number of timers are required, and the time setting thereof is also troublesome.

The purpose of the present invention is to eliminate the above-mentioned drawbacks, and to provide a phase-matched signal oscillator that can obtain a desired ratio of phase-matched signals even when the drum rotation speed is changed by using one proximity switch for the blanking signal. We aim to provide the following.

The phase matching signal oscillator of the present invention includes a proximity switch to obtain a blanking signal of a% of the drum rotation period T, and a phase matching signal of b% of T (a>b) at the center of this blanking signal. An oscillator that generates an output pulse of a constant frequency in synchronization with the blanking signal, a frequency divider circuit that divides the frequency of the pulse output from the oscillator during the blanking signal period, and a frequency divider circuit that divides the output pulse width of the frequency divider circuit. a pulse width conversion circuit that generates a phase matching signal having a pulse width of a predetermined multiple at the center of the blanking signal, and a control input to the frequency dividing circuit for switching a frequency division ratio according to the rotational speed of the drum. is provided, and the frequency division ratio of the frequency dividing circuit is switched according to the drum rotation speed, so that a phase matching signal of a constant ratio b% of the rotation period T is obtained at the center of the blanking signal regardless of the drum rotation speed. It is characterized by:

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a diagram for explaining the principle of the phase matching signal oscillator of the present invention.

Reference numeral 1 indicates a rotating drum of a facsimile machine, and as this drum is rotated by a drive system 2, main scanning is performed with a fixed -\rad (not shown) on the drum.

A proximity switch 3 is provided near the drum 1, and the switch is turned 0NOFF by 10 rotations of the drum, so that a blanking signal can be obtained.

A blanking signal, which is the output of the proximity switch 3, is supplied to an oscillator 4 to control the oscillator, and generates an output pulse of a constant frequency in synchronization with the blanking signal.

The output of the oscillator 4 is supplied to a frequency divider 5 and divided by a frequency division ratio according to the rotation speed of the drum 10.

In order to switch the frequency division ratio according to the rotational speed of the drum 10, a frequency division ratio switching signal for switching the frequency division ratio according to the change in the drum rotational speed is supplied to the control input of the divider 50.

Even if the rotation speed of the drum 10 is changed, the pulse width of the output signal of the frequency divider 5 does not change as a percentage of the drum's one rotation period.
The output of the frequency divider 5 can be used as a phase matching signal in the blanking signal.

The blanking signal time is 5 of one rotation period of the rotating drum 1.
FIGS. 2 and 3 show block diagrams and waveform diagrams in the case where the blanking signal includes two phase matching signals at the center of the blanking signal.

The output of the inverter 10 is connected to one input of the NAND gate 13 via the capacitor 11 and the resistor 12, and the NAND
An oscillation circuit is constructed by connecting the output of the D gate 13 to the input of the inverter 100 via the resistor 14.

Further, a resistor 15 is connected between the output and the input of the inverter 10, and a resistor 16 is connected between the input and output of the NAND gate 13.

The other input of the NAND gate 13 is supplied with the output of the proximity switch 3 for obtaining a blanking signal.

Therefore, this oscillation circuit is gated by the blanking signal which is the output of the proximity switch 3, and the oscillation circuit oscillates at a constant frequency in synchronization with the blanking signal.

The output of NAND gate 13 also provides a divider circuit 170 input.

A frequency division ratio switching signal for switching the division ratio according to the rotational speed of the drum is supplied to the control input of the frequency division circuit 170 to control the frequency division circuit and switch the division ratio according to the rotational speed of the drum.

The output of the frequency dividing circuit 17 is converted into a decimal counter and an inverter 1.
8 to the pulse width conversion circuit 19, and obtain a phase matching signal from the output of the pulse width conversion circuit.

Mathematically showing the operation of the above device, Be able to express it as

However, T is the drum rotation period, f is the oscillation frequency of the oscillation circuit, and 1/ is the frequency division ratio of the frequency divider circuit.

In other words, the oscillation frequency f of the oscillation circuit output is
The frequency is divided by the frequency division ratio to become f/, and this period 1/L is multiplied by 4 in a pulse width conversion circuit to obtain a phase matching signal T×20I).

A waveform 20 shown in FIG. 3 is a waveform representing a blanking signal, and the fifth period of one period T is the blanking signal.

Waveform 20' shows the blanking signal portion of waveform 20 with the time axis enlarged, and waveform 21 is the output waveform of frequency dividing circuit 17 corresponding to the time axis of waveform 20'.

That is, the output of the frequency dividing circuit is a signal that always contains 10 pulses in the blanking signal of the 5 major rotation periods of the drum.

The pulse width conversion circuit 19 extracts four pulses from among the output pulses of the frequency dividing circuit 17, and can obtain a phase matching signal whose pulse width is a factor of two of the drum rotation period.

Waveform 22° and waveform 23 are waveforms in the process of obtaining a phase matching signal from the output of the frequency dividing circuit 17 in the pulse width conversion circuit 19, and convert the output pulse width of the frequency dividing circuit to twice and four times, respectively.

The waveform 24 is the output waveform of the pulse width conversion circuit 19, and the pulse width is four times the output pulse period of the frequency dividing circuit, and is TX2%.

Therefore, even if the rotational speed of the rotating drum is changed, it is possible to obtain a blanking signal and a phase matching signal whose ratio to the drum rotation period is always constant.

International organization for the operation of international telegraph and telephone services and wired communication technology (
In the example recommended for facsimile by CCITT (abbreviation: CCITT), when transmitting an A4 size document in 2 minutes, 3 minutes, 4 minutes, and 6 minutes, respectively, the period T should be 1, ±2, 9,
54 54 54 54 54 seconds, respectively.

Now, if T = 54 seconds is selected as the reference period and 7200 Hz is selected as the oscillator frequency f, a phase matching signal of 2% of the reference period T is obtained from the pulse width conversion circuit 19 when n = 4. Ru.

On the other hand, when the period T is set to -2545454, respectively, by selecting the value of n to 6 and 8°12, respectively, a phase matching signal of 2φ with each period is obtained.

Generally, the oscillation frequency of the oscillator is determined by considering the circuit configuration, etc., but it can be set in a wide range from several tens of Hz to several tens of KHz.

The present invention is not limited to the example described above, but can be modified in many ways.

Furthermore, it is also possible to apply the present invention to devices other than facsimile devices.

According to the present invention, phase matching signals of facsimile machines having multiple scanning speeds can be obtained by a simple method, and a transmitter or receiver to which the present invention is applied can be used as a receiver or transmitter having various scanning speeds. This means that it can be used with the machine.

Furthermore, the present invention has the advantage that there are no mechanical components, which allows the device to be made smaller and does not restrict freedom of design.

[Brief explanation of drawings]

Figure 1 is a diagram schematically showing the configuration of the phase matching signal oscillator of the present invention, Figure 2 is a block diagram showing the configuration of an example of the phase matching signal oscillator of the present invention, and Figure 3 is a waveform diagram of each part thereof. . 1...Drum, 3...Proximity switch,
4... Oscillator, 5... Frequency divider, 20,
20'...Blanking signal, 24...
...Phase matching signal.

Claims (1)

[Scope of utility model registration request] A proximity switch that obtains a blanking signal of a% of the drum rotation period T, and a proximity switch that obtains a blanking signal of a% of the drum rotation period T, and b% of T (
In order to obtain a phase-matched signal with a>b), an oscillator that generates an output pulse of a constant frequency in synchronization with the blanking signal, and a frequency division of the pulse output from the oscillator during the period of the blanking signal. a frequency dividing circuit; and a pulse width converting circuit for generating a phase matching signal having a pulse width that is a predetermined multiple of the output pulse width of the frequency dividing circuit at the center of the blanking signal; A control input is provided for switching the frequency division ratio according to the rotation speed, and the frequency division ratio of the frequency division circuit is switched according to the drum rotation speed,
A phase matching signal oscillator characterized in that a phase matching signal of a constant ratio b% of the rotation period T is obtained at the center of a blanking signal regardless of the drum rotation speed.