DE3347149A1 - Arrangement for transmitting electrical information signals - Google Patents

Abstract

An arrangement for alternate transmission of electrical information signals between a camera and a flashlight unit which can be connected thereto is proposed which consists of a first circuit arrangement, which is arranged on the camera side, and a second circuit arrangement belonging to the flashlight unit. These circuit arrangements emit information signals, in a sequence initiated by the camera or flashlight unit, in the form of an electrical voltage. They are connected to the interface between the camera and flashlight unit by a single contact via which the information signals flow.

Description

Arrangement for the transmission of electrical information signals

The invention relates to an arrangement for alternating transmission electrical information signals between a photographic camera and a with this connectable flash unit.

Such a circuit arrangement is in modern, high degree automated, interacting with a flashlight directly or via an adapter Cameras required to determine when to take flash exposures whether suitable recording conditions, such as B. attached flash unit or whose willingness are present.

To meet such Erfqßernisse it is known on the camera side Slip-on shoe for the flash unit or its adapter next to the contact for the ignition of the lightning bolt, a further contact must be chen the Camera in the form of a rectangular alternating voltage receives the information that the flash unit is attached or ready to flash. Furthermore, there is usually a third one Contact available through which the flash unit sends a signal to the camera to switch off the flash receives.

It is also known to connect the output to the third contact on the accessory shoe a current amplifier receiving the current from a photodiode place.

DE-OS 32 20 330 is a flash device for photographic cameras known in which a signal transmitter at least two different signals gives a common connection contact and a control circuit prevents while one signal is being sent, another signal can be sent to the contact can.

The disadvantage of the acquaintance is the high level of contact required for the transfer several different pieces of information in signal form is required and the represents a considerable reduction in the functional reliability of the entire arrangement.

Fs is: therefore the object of the present invention to specify an arrangement when transmitting information in signal form between the camera and flash unit or the adapter assigned to this offers a high level of functional reliability and the The connection between the camera and flash unit is only established through a small number of contacts or adapter manufactures.

According to the invention, for an arrangement of the type mentioned at the outset this object is achieved in that a first and a second circuit arrangement are available, of which the first is arranged on the camera side and the second on the device side and the information signals in a sequence initiated by the camera or flash unit output in the form of an electrical voltage or current (signals), and that at the Interface between camera and flash unit at least one contact for connection the circuit arrangements is provided through which the information signals flow.

Further advantageous refinements of the invention are the subject matter of the subclaims.

In the drawing, the invention is shown schematically in exemplary embodiments shown and described in more detail below: They show: FIG. 1 an inventive Circuit arrangement, Fig. 2a and 2b, diagrams of the voltage curve of to be transmitted Signals (volume modulated), FIG. 3 shows a voltage diagram of signals to be transmitted (pulse code modulated), FIG. 4 shows a first variant of the circuit arrangement according to the invention and FIG. 5 shows a further exemplary embodiment.

In Figures 1, 4 and 5, 1 denotes an interface, the separation between a camera 2 and a flash unit 3 or an adapter represents. The camera 2 contains a circuit arrangement located to the left of the cutting line 1 4, the flash device 3, a circuit arrangement 5 arranged to the right thereof.

The camera-side circuit arrangement 4 contains an operational amplifier 6, at its non-inverting input one of a not shown Voltage source fed resistor 7 is. At the inverting input of the OP amplifier 6 there are resistors 8, 9, over which the one tapped by a potentiometer 10 Voltage flows, which affects the sensitivity of the film used in the camera 2 is equivalent to. The output of the operational amplifier 6 is via another resistor 11 fed back to its non-inverting input. Also is the exit the operational amplifier 6 is followed by a diode 12.

The circuit arrangement 4 is an LED control device 13 for display purposes assigned, which can also include a setting device that can be used in Attaching the flash unit to the camera, the shutter automatically switches to flash mode (e.g. 1/90 sec).

The circuit arrangement 5 on the flash device side comprises a pulse generator 14, the output of which is followed by a resistor 15, is one of the output signals of the generator 14 controlled semiconductor switch 16, as well as a Operational amplifier 17, in front of its non-inverting input a capacitor 18 is placed.

The circuit arrangements 4 and 5 are through a single, in the Intersection line 1 between camera 2 and flash unit 3 contact 19 connected. The arrangement described so far works in the following way: The generator 14 gives no or at corresponding input signals E1, E2 at its output but a square-wave voltage with a fixed amplitude (e.g.

4 or 6 Hz). The input signal E1 can, for example, come from the voltage control a discharge capacitor, not shown here, is formed in the flash unit 3 will. If this discharge capacitor is not fully charged, the input signal is E1 = 0 volts. When the charging voltage is reached, E1 becomes the "L" signal with, for example G volts, whereby at the output of the pulse generator 14 a fixed square-wave voltage appears with e.g. 4 Hz and an amplitude of 6 volts.

While the flash is triggered, E1 goes back to 0 volts and the Square-wave voltage at the generator output disappears.

Was now during the flash by the exposure metering circuit not shown here the camera 2 has correctly supplied the switch-off signal for the flash, the pulse generator is activated 14 caused by an input signal E2 to emit an 8 Hz frequency for about 2 seconds. It is known that with this signal sufficient flash brightness speed is shown.

The pulse trains influenced by the signals E1 and E2 are available to the camera 2 via the resistor 15 and contact 19 at the output of the generator 14 for the LED control 13 and, if necessary, for an automatic setting of the Camera shutter available at 1/90 sec in flash mode.

However, the voltage at contact 19 does not reach the 6 volt amplitude, since the Genaator 14 via the resistor 15 from the operational amplifier 6 and his Wiring with the resistors 7 - 9 and 11 as well as the diode 12 is loaded.

The operational amplifier 6 itself receives its input signal from the potentiometer 10, the grinder 10a of which there is one proportional to the sensitivity of the film used Voltage is tapped and additionally from one end lOb of the same potentiometer as a reference.

The semiconductor switch 16 is activated by the output of the pulse generator 14 controlled; in such a way that it is only in the positive half-waves of the generator 14 output pulse trains becomes conductive. In this way, the output of the flash unit is available Operational amplifier 17 a constant voltage corresponding to the film speed, the one input of a comparator not shown here for the flash shutdown can be supplied within an exposure control circuit.

The course of the tensions created with the arrangement described above transmitted between camera 2 and flash unit 3 is shown in FIGS. 2a and 2b shown diagrammatically in a frequency response. This corresponds to that in FIG. 2a The voltage curve shown for a film speed setting of e.g. 150DIN and that in Fig. 2b 0, for example, 36 DIN.

If FIGS. 2a and 2b show amplitude-modulated signals, then in 3 shows a possible variant, namely a pulse code modulated signal, in the diagram shown.

The signals are then subjected to such a modulation when their processing in the camera and / or flash unit or an adapter assigned to this should preferably be done digitally. The Pu0.mulation is sufficient in technology known and is not explained further here.

In the diagram, the times tl, t2 and t3 indicate the time of a Period while the flash is triggered at point t4. That way the pulse can follow within a period of a certain film speed be assigned.

In the variant shown in FIG. 4, the operational amplifier is on the camera side 6 and its wiring are omitted and the potentiometer 10 by a control resistor 20 replaced with upstream protective resistor 21. The device takes its place of the pulse generator 14, a controlled current source 22.

The power source 22 is from the flash unit 3 or its The adapter generated a pulsed frequency, so that the voltage applied to the contact 19 also pulsates and pulse trains according to FIGS. 2a and 2b arise.

In the camera 2, the LED control device is in the manner described in connection with FIG 13 controlled, with which the switching of the shutter speed to a flash corresponding (e.g. 1/90 sec) can be carried out.

With the positive half-waves of the pulsating at contact 19 Signal, the switch 16 is closed sen. The tension flowing over him becomes stored by the condenser 18 and is then available at the output of the on the capacitor 18 following operational amplifier 17 low resistance.

In the embodiment 2 according to FIG. 5, a digital transmission takes place the signals between camera 2 and flash unit 3. This takes the place of the camera the controllable resistors 10 and 20 outputting analog voltages are a pulse generator 23, the output of which is connected to the base of a transistor 25 via a resistor 24 is. The output from the pulse generator 23, for example in their upper half-waves the information about the film speed carrying signal pulse trains are from the Collector of transistor 25, the emitter of which is connected to a grounded resistor 26 is passed through a resistor 27 to the contact 19, via which it is connected to a device-side Part of the arrangement Chen shift register 28 arrive. A memory 29 connected downstream of the shift register 28 stores the signals, see above that they are always available. From a D / A converter following the memory 29 30 the information signals are converted into analog voltages and one here not shown with the comparator arranged in the flash unit 3 or its adapter supplied, with the output signal of which the flash is switched off.

Claims (8)

Claims 1. Arrangement for alternate transmission of electrical Information signals between a photographic camera and one that can be connected to it Flash unit, d u r g e k e nn n e i c h n e t, that a first (4) and a A second (5) circuit arrangement is present, the first (4) of which is on the camera side and the second (5) is arranged on the device side and in one of the camera (2) or Flash device (3) initiated the information signals in the form of an electrical sequence Output voltage or current, and that at the interface (1) between Camera (2) and flash unit (3) at least one contact (19) for connecting the circuit arrangements (4,5) ~ is provided over which the information signals in both directions flow. 2. Arrangement according to claim 1, d a d u r c h g e -k e n n z e ic h n e t that the circuit arrangements (4,5) with electronic components (6-12; I4-18, 20,21, 14-27) are equipped, which control the flow of signals from the camera (2) to the Effect the flash unit (3) and vice versa more or less at the same time. 3. Arrangement according to claim 2, d a d u r c h g e -k e n n z e i c h n e t that the electronic components selectively acting resistor networks (6-12; 20,21) and electronic switches (16) with which analog information signals be generated. 4. Arrangement according to claims 1 to 3, d a d u r c h g e k e n n indicate that one of the circuit arrangements (4, 5) comprises a device which subjects the analog signals to a multiplex sequence. 5. Arrangement according to claim 2, d a d u r c h g e -k e n n z e i c h Not that the electronic components generate digital information signals Elements (23-30) are. 6. Arrangement according to claim 1, d a d u r c h g e k e n n z e i c h n e t that means are provided with which that from the flash unit (3) to the camera (2) flowing signal (e.g. broadband signal) further signals can be superimposed. 7. Arrangement according to claims 1 to 6, d a -d u r c h g e k e n n e i n e t that means for pulse code modulation of the signals are included. 8. An arrangement according to claim 6, d a d u r c h g e -k e n n z e i c h n e t that means for amplitude modulation of the signals are provided.