1. A frequency multiplying circuit for multiplying a first frequency, the circuit comprising: a transadmittance portion having a first transfer characteristic, the transadmittance portion having two input terminals for a signal of said first frequency; and a transimpedance portion having a second transfer characteristic, the transimpedance portion having two output terminals for a signal of a second frequency higher than the first frequency as an output of said multiplying circuit, wherein a transfer characteristic of the transimpedance portion is steeper than a transfer characteristic of the transadmittance portion, and wherein a modulation range of the transadmittance portion is greater than a modulation range of the transimpedance portion.
2. The circuit according to claim 1, wherein the transadmittance portion has a first symmetrical DC amplifier with a first transistor circuit, a second transistor circuit, and a first constant-current source that is connected to a common emitter terminal of the first transistor circuit and the second transistor circuit.
3. The circuit according to claim 2, wherein the transimpedance portion has a second symmetrical DC amplifier that has a third transistor circuit and a fourth transistor circuit, wherein the third transistor circuit and the fourth transistor circuit each include at least one transistor, and a resistor connected between the collector and the base of the transistor and said transimpedance portion further including a second constant current source, and wherein the second constant current source is connected to a common emitter terminal of the third and fourth transistor circuits.
4. The circuit according to claim 3, wherein at least one of the first, second, third or fourth transistor circuits has at least one bipolar transistor.
5. The circuit according to claim 3, wherein at least one of the first, second, third or fourth transistor circuits has at least one field-effect transistor.
6. The circuit according to claim 3, wherein first partial currents of the two constant-current sources are collected at a first node that is connected to an operating voltage of the circuit through a first load resistor, second partial currents of the two constant-current sources are collected at a second node that is connected to the operating voltage through a second load resistor, and wherein a first terminal of the transimpedance portion is connected to the first node and a second terminal of the transimpedance portion is connected to a second node.
7. The circuit according to claim 1, wherein the transadmittance portion and the transimpedance portion are integrated on a chip with a transmit path and a receive path.
8. The circuit according to claim 7, wherein an electrical connection is formed between the terminals of the transimpedance portion and a transmit path or a receive path.
9. The circuit according to claim 8, wherein an electrical connection is formed between the terminals of the transadmittance portion and a voltage-controlled oscillator.
10. The circuit according to claim 9, wherein an output frequency of the voltage-controlled oscillator is two thirds of a transmit frequency, halved for internal signal processing and tripled by the circuit.
11. The circuit according to claim 1, wherein the transadmittance portion is in series with the transimpedance portion.
12. A frequency multiplying circuit for multiplying a first frequency, the circuit comprising: a transadmittance portion having a voltage-current transfer characteristic, the transadmittance portion having two input terminals for a signal of said first frequency; and a transimpedance portion having a current-voltage transfer characteristic, the transimpedance portion having two output terminals for a signal of a second frequency, which is higher than said first frequency, and which is output from said multiplying circuit, wherein a modulation range of the transadmittance portion is greater than a modulation range of the transimpedance portion.
13. The circuit according to claim 12, wherein the current-voltage transfer characteristic of the transimpedance portion is steeper than voltage-current transfer characteristic of the transadmittance portion.
14. The circuit according to claim 1, wherein said transadmittance portion includes two transadmittance output terminals and said transimpedance portion includes two transimpedance input terminals and wherein said two transadmittance output terminals are directly connected to said two transimpedance input terminals.
15. The circuit according to claim 12 wherein said transadmittance portion includes two transadmittance output terminals and said transimpedance portion includes two transimpedance input terminals and wherein said two transadmittance output terminals are directly connected to said two transimpedance input terminals.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An electric bending endoscope comprising:
an inserting portion having a bending portion which is inserted in a subject;
an operation wire which is inserted in the inserting portion for bending the bending portion;
a motor for supplying a driving force to the operation wire for bending the bending portion;
a first unit for holding the motor;
a driving force transmitting member which transmits the driving force supplied from the motor to the operation wire in order to bend the bending portion, the driving force transmitting member being connected to the operation wire via a connecting portion;
a second unit for holding the driving force transmitting member;
a first connecting member for connecting the first unit and the second unit so that the driving force of the motor maybe transmitted to the driving force transmitting member; and
a second connecting member for connecting the second unit and the inserting portion so that the bending portion many be bent by the driving force transmitted from the driving force transmitting member.
2. An electric bending endoscope according to claim 1, wherein the driving force transmitting member is rotatably supported by the second unit in order to operate a bending operation member passed through the inserting portion in accordance with the driving of the motor, the first unit has an attaching hole which accommodates a rotating shaft of the driving force transmitting member and at least three positioning holes arranged near the attaching hole, and the first connecting member has a hole through which the rotating shaft is passed, a projecting and positioning piece which is accommodated in the attaching hole, and at least three projecting and positioning pins which are fit into the positioning holes.
3. An electric bending endoscope according to claim 2, wherein the first unit is further provided with an opening which connectably accommodates the second unit to the motor and the driving force transmitting member, and a guide hole which guides and accommodates the rotating shaft upon mounting the second unit via the opening.
4. An electric bending endoscope according to claim 1, wherein the second connecting member holds a universal cord for connecting the electric bending endoscope to a peripheral device, wherein the first unit comprises an outer frame and an inner frame for holding the motor, and the second connecting member is connected to the inner frame and the inner frame is accommodated in the outer frame so as to be at least partially exposed to form an exposed portion, and the second connecting member is fixed to the exposed portion.
5. An electric bending endoscope according to claim 4, wherein the second connecting member has a ring-shaped holding portion for holding the universal cord and a fixing portion for fixing the holding portion to the inner frame at at least three positions.
6. An electric bending endoscope according to claim 5, wherein the holding portion has a plurality of screw holes on a peripheral surface and the universal cord is fit by screw operation of a screw via a screw hole arranged to a connector at an edge portion of the universal cord and the screw holes of the holding portion.
7. An electric bending endoscope according to claim 4, further comprising:
a fixing member which fixes the inner frame to a main frame in the second unit.
8. An electric bending endoscope according to claim 7, wherein the main frame is positioned to the inner frame by using a positioning tool for positioning the main frame in the second unit in three-axis directions to the inner frame, and the inner frame and the main frame in the second unit are fixed by using a fixing member for fixing them.
9. An electric bending endoscope according to claim 8, wherein a positioning and fixing member for positioning and fixing the main frame in the second unit in three-axis directions to the inner frame is arranged to a connecting portion of the inner frame and the main frame.
10. An electric bending endoscope according to claim 7, wherein the bending operation member is constituted such as to slide with respect to the second unit in accordance with the driving of the motor when bending the bending portion, and the main frame in the second unit is arranged so that a signal cable which is passed through the endoscope for transmitting an endoscope image pick-up signal, a light guide for transmitting illumination light, and the bending operation member are detached.
11. An electric bending endoscope according to claim 1, wherein the first unit comprises an inner frame for holding the motor and an outer frame for accommodating the inner frame, the inner frame having a holding member for holding a universal cord for connecting the electric bending endoscope to a peripheral device.
12. An electric bending endoscope comprising:
an inserting portion which is inserted in a subject;
bending means for bending the inserting portion;
driving force supplying means for supplying a driving force for bending the inserting portion;
driving force transmitting means which transmits the driving force supplied from the driving force supplying means to the inserting portion in order to bend the inserting portion;
first connecting means for connecting the driving force supplying means and the driving force transmitting means in order to transmit the driving force supplied from the driving force supplying means to the driving force transmitting means; and
second connecting means for connecting the driving force transmitting means and the inserting portion in order to transmit the driving force transmitted to the driving force transmitting means to the bending portion.