JPS6358439B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a remote control device that performs signal transmission using the FSK method.

First, the outline of the remote control device according to the present invention will be explained in the first part.
This will be explained with reference to FIGS. 3 to 3. Figure 1 shows a block diagram of the transmitter, and shows the setting status of the coding switch circuit 1a (on/off of each switch).
Accordingly, the address setting circuit 1 obtains a signal S consisting of fundamental signal frequencies having frequencies f ₁ and f ₂ . This signal S modulates the carrier wave of frequency fc obtained by the carrier wave oscillation circuit 2, and passes through the amplifier circuit 3 to the antenna 4.
Send from 5 is a transmission switch, and 6 is a power supply. Figure 2 shows the block diagram of the receiver.
The signal received by antenna 7 is sent to high frequency amplification circuit 8
After being amplified by the frequency conversion circuit 9 and frequency-converted by the frequency conversion circuit 9, the high frequency component is cut by the low-pass filter circuit 10 to form the signal S, which is amplified by the amplifier 11.
Reference numeral 12 denotes a signal separation unit that is a subject of the present invention, and the signal S has frequencies f ₁ (e.g. 10KHz) and f ₂ (e.g.
Bandpass filter 13, 14 for 15KHz)
They become signals B and C, respectively, and are sent to the detection circuit 15.
The signal is switched and sent to detection circuits 16 and 17, and signals D and E are obtained. This signal is identified by the address identification circuit 18, and if it matches the code set in advance in the receiver, the output signal F is output to load 1.
9, and operates a control element such as a relay to perform a predetermined operation of, for example, audio equipment or power equipment. FIG. 3 shows signal waveforms and coding contents at each of these stages, where A is the coding content and S, B, C, D, E, and F are the above-mentioned signal waveforms. L ₁ and L ₂ of B and C indicate their respective switching levels.

In the above-mentioned remote control device, the same number of comparators as the fundamental signal frequency used for coding are used in the signal separation section, and the output of the amplifier is inputted to one input terminal of each comparator via each tank circuit, and A bias voltage common to each comparator is input to the other input terminal, and this bias voltage is adjusted at one location. This bias voltage determines the threshold level of the comparator. FIG. 4 shows the configuration of the signal separation section of this conventional example, and FIG. 5 shows the signal waveforms of each section. Note that this example describes a case where three types of fundamental signal frequencies are used.

The signal waveform a in FIG. 4 is amplified by the amplifier 11, and the signal waveform a in FIG.
Through this, signal waveforms b, c, and d are obtained, respectively. and each comparator 24,2
The signal waveforms e, f, and g are applied to the output terminals by being applied to the signal input terminals 5 and 26 and switched by the threshold level _Vt . Here, a bias voltage obtained at the connection point between the low resistor 27 and the variable resistor 28 is applied to the other input terminal of each of the comparators 24, 25, and 26, and the threshold level _Vt is commonly determined. , variable resistor 28
Sensitivity can be adjusted by

However, in conventional examples that use comparators in this way, the comparators are expensive elements, so in this type of device that requires multiple comparators, the entire device becomes expensive.
Furthermore, since the current consumption is large, the power consumption is large and there is a lot of waste, and especially in the case of a device using a battery as a power source, there is a problem that it is not preferable from the viewpoint of battery life.

The present invention was made with the aim of solving such problems, and uses a C-MOS inverter that is not provided with a threshold level setting terminal to perform the same function as a comparator, and is inexpensive. In addition to providing a remote control device,
It is also designed to reduce power consumption.

An embodiment will be described below with reference to FIGS. 6 and 7. Furthermore, since the signal waveform in the one shown in FIG. 6 is the same as that in the conventional example shown in FIG.
This will be explained using FIG. 5.

In FIG. 6, the signal waveform a amplified by the amplifier 11 is transmitted to each bandpass filter 21, 22, 23.
and signal waveforms b, c, and d are obtained, respectively. Each of these signals is connected to a resistor 31,
32 and 33 to each C-MOS inverter 34,
The signals are applied to input terminals 34a, 35a, and 36a of 35 and 36, and signal waveforms e, f, and g are obtained on the output terminal side.

Next, this point will be explained in detail. The ground side of each bandpass filter 21, 22, 23 is different from the conventional example shown in FIG. . In other words, the ground side of each tank circuit is commonly grounded using a capacitor for AC, and a variable bias voltage V _B is applied for DC. Here C
-The threshold level V _IH of the MOS inverter is determined by V _IH = A × V _DD (A: 0.3 to 0.7), but the effective threshold V _S is V _S = V _IH − V _B , which is determined by the bias voltage. Can be adjusted.
Furthermore, as mentioned above, the threshold level V _IH varies considerably, but this is when the entire product is considered as one population, and between each C-MOS inverter in the same package formed on the same chip. There is almost no difference, and they can be considered practically the same. Therefore, if elements in the same package are used, the same bias voltage can be obtained from the sensitivity adjustment section, and by adjusting this bias voltage, the sensitivity of each C-MOS inverter can be adjusted using one variable resistor 28. As described above, signal waveforms e, f, and g can be obtained by switching signal waveforms b, c, and d at desired levels.

FIG. 7 shows the relationship between V _IH , V _S and V _B , and the threshold value V _S can be adjusted by changing the bias voltage V _B. Therefore, although FIG. 5 was used in this embodiment, the threshold level V _t for waveforms b, c, and d in the same figure is as follows:
In the case of this embodiment, the threshold value is V _S.

Note that if C-MOS inverters that are not in the same package are used together, even if there is a low-sensitivity element, the sensitivity of the entire device must be kept low to prevent malfunctions of other high-sensitivity elements, and the entire device will have low sensitivity. If a sensitivity adjustment resistor or the like is attached to each C-MOS inverter to prevent this, the cost will increase and the structure and operation will become complicated, which is not desirable.

The present invention performs signal transmission using the FSK method, and also separates and extracts a plurality of fundamental signal frequencies constituting the code of the transmitted signal using a bandpass filter composed of a parallel circuit of a capacitor and a coil.
The presence or absence of the output of this bandpass filter is detected by a detection circuit whose detection sensitivity can be freely adjusted. The output of this detection circuit is detected by a detection circuit. From the output, an identification circuit identifies the code of the transmitted signal and responds to this code. In a remote control device that performs predetermined control using the same chip, a plurality of C-MOS inverters are formed on the same chip and detect the presence or absence of the output of each bandpass filter, and a common cable is connected between each of the bandpass filters and the ground. The detection circuit consists of a sensitivity adjustment section that is connected to the ground side of each bandpass filter and applies a bias voltage to adjust the switching level of the C-MOS inverter. Since multiple C-MOS inverters are used, even if the threshold levels of the C-MOS inverters themselves have large variations, it is possible to eliminate variations in the threshold levels.Moreover, a common bias voltage can be applied to the sensitivity setting section. Since it is applied to the ground side of the band pass filter, the threshold level can be set even if the C-MOS inverter does not have a setting terminal, and
It can also absorb absolute variations. Therefore, the above C-MOS inverter can be used in the same way as a comparator. Furthermore, for example, it becomes possible to adjust the sensitivity of all elements using one variable impedance element such as a variable resistor.
Therefore, the device can be constructed at a lower cost than when a comparator is used, and power consumption can be significantly reduced, resulting in an energy-saving type device.
Moreover, it is possible to obtain a remote control device that has a simple configuration and is easy to manufacture and adjust.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a transmitter of a remote control device according to the present invention, FIG. 2 is a block diagram of a receiver of the same, FIG. 3 is a diagram showing signal waveforms of the same, and FIG. FIG. 5 is a diagram showing the signal waveforms of the same as above, FIG. 6 is a wiring diagram of the main part of the embodiment of the present invention, and FIG. 7 is an explanatory diagram showing the voltage relationship of the same. 11 is an amplifier, 15 is a detection circuit, 16 and 17 are detection circuits, 18 is an address identification circuit, 21, 2
2 and 23 are band pass filters, 27 is a resistor, 2
8 is a variable resistor, 34, 35, 36 are C-MOS inverters, 34a, 35a, 36a are input terminals,
37 is a capacitor.

Claims (1)

[Claims] 1 In addition to transmitting signals using the FSK method, multiple fundamental signal frequencies that make up the code of the transmitted signal are each separated and extracted using a bandpass filter consisting of a parallel circuit of a capacitor and a coil. The presence or absence of an output is detected by a detection circuit whose detection sensitivity can be adjusted freely, and an identification circuit identifies the code of the transmitted signal from the output of this detection circuit detected by a detection circuit, and performs a predetermined control according to this code. In a remote control device, a plurality of C-MOS inverters are formed on the same chip and detect the presence or absence of an output from each bandpass filter, and a plurality of C-MOS inverters are commonly connected between each of the bandpass filters and the ground, and each A remote control device characterized in that the detection circuit is constituted by a sensitivity adjustment section that applies a bias voltage for adjusting a switching level of a C-MOS inverter to the ground side of a bandpass filter.