US1996737A

US1996737A - Quartz oscillator arrangement

Info

Publication number: US1996737A
Authority: US
Inventors: Bechmann Rudolf
Original assignee: Telefunken AG
Current assignee: Telefunken AG
Priority date: 1931-04-14
Filing date: 1932-04-14
Publication date: 1935-04-09
Anticipated expiration: 1952-04-09

Description

April 9, 1935. R. BECHMANN QUARTZ OSCILLATOR ARRANGEMENT Filed April 14, 1932 INVENTOR RUDOLF BFCHMANN BY I Mm,

ATTORNEY Patented Apr. 9, 1935 1,996,737 QUARTZ osornm'roa manoarmn'r Rudolf Bechmann, Berlin, Germany, assignor to Telefunken Gesellschaft fiir Drahtlose Telegraphic in. b. 11., Berlin, Germanma corporation of Germany PATENT I OFFICE Application April 14, 1932. Serial No. 605.2245" In Germany April 14,1931

7 Claim This invention relates to a quartz crystal oscillator arrangement particularly to the type in which the crystal and its associated electrodes are enclosed within a glass vessel. An object of this invention is tosimplify and improve .quartz crystal holders of the enclosedtype. This invention will best be understood by the following specification and accompanying drawing. In the drawing Fig. 1 illustrates the general circuit arrangement of the crystal oscillator, Fig. 2 is a sectional view of the improved quartz crystal holder and its glass envelope. Referring now to the circuit scheme most widely used for quartz oscillators is as shown in Figure 1, where l denotes the crystal holder the quartz crystal being interposed between two parallel electrodes, 2 the grid leak (resistance) connected in parallel to them, 3 the amplifier tube required to maintain the oscillations, and l a choke-coilconnected in the plate circuit thereof. It has been found to be of advantage with aview to maintain constancy or stability not to tune the said choke-coil by a condenser, in which case the dimension thereof is but immaterial as regards its influence upon the spontaneously arising frequency of the arrangement.

It is known to be necessary in the prior art that the quartz crystal should be confined within a temperature regulating container (thermostat) in order that the wave length may remain unafiected by fluctuations of the ambient temperature. 0n the other hand, it is known, however, that such intended frequency variations or changes as may become necessary in the operation of radio transmission systems can be produced by controlled variation of the temperature of the quartz crystal oscillator. For this purpose it is necessary to use a thermostat of very small thermal inertia in order that the intended frequency variations may be occasioned with adequate speed. As a result, also the heating time of the thermostat will be reducedin the desired manner to a marked degree. The invention hereinafter to be disclosed has for its purpose to satisfy the said requirements.

According to the present invention the geometric dimensions and the heat capacity of the thermostat are reduced to the minimum. Furthermore, the crystal oscillator conjointly with such means as are used and provided for temperature regulation are accommodated inside a 'more or less perfectly evacuated container in order that the heat losses and thus the heating energy may be minimized.

One embodiment of the basic idea of the invention is shown in Figure 2. The piezo-electric quartz crystal II bears upon a metallic body I2 which constitutes one electrode of the crystal and its circuit. The cooperating electrode I3 is placed, for instance, by the aid of a glass ring l4 so as to insure the desired distance and is supported, e. g., by the aid of a spring 5. The heating of the quartz crystal is effected by a windin 6 which is made from resistor wire. The temperature of the device may be regulated and controlled by various auxiliaries. For the arrangement hereinbefore disclosed there is particularly suited for this purpose a measuring winding 1 which consists of a wire of a high temperature coefilcient, such asv copper. This measuring winding in well known manner may be included in one arm of a Wheatstone bridge arrangement which, when the desired or intended temperature is reached or prevails is in a state of equilibrium, whereas when the normal temperature is exceeded a heating current of suitable value is released (caused to act) in the heating winding, though it will be understood that for the control of the heating also another thermal contact element or means such as a bimetal strip or breaker may be used.

The construction elements hereinbefore mentioned are preferably accommodated inside a glass vessel so that the assembly has the appearance approximately of an amplifier tube.

I claim:

1. A piezo-electric crystal holder comprising a base having connection pins and a sealed evacuated vessel above said base, an electrode sup ported above said base, an insulated ring secured to the upper portion of said electrode, a piezoelectric crystal resting on said electrode, a second electrode spaced by said insulated ring and disposed above the said crystal, and a heating resistance surrounding said first mentioned electrode for controlling the temperature of said crystal.

2. A piezo-electric crystal holder comprising a base having connection pins, a sealed evacuated vessel above said base, an upper electrode, a lower electrode supported by a central stud, a piezoelectric crystal resting on said electrode, an insulating ring enclosing said crystal and spacing it from said upper electrode, and a heating resistance surrounding said lower electrode for controlling the temperature of said crystal.

3. A piezo-electric crystal holder comprising a base having connection pins, a sealed evacuated vessel above said base, an upper electrode, a lower circular electrode supported by a central stud, a

piezo-electric crystal resting on said electrode, an insulating ring enclosing said crystal and spacing it from said upper electrode, and a heating resistance surrounding said lower electrode for controlling the temperature of said crystal.

4. A piezo-electric crystal holder comprising a base having connection pinsa sealed evacuated vessel above'said base, an upper electrode, a lower circular electrode supported by a central stud, a piezo-electric crystal resting on said electrode, an insulating ring enclosing said crystal and spacing it from said upperelectrode, and a plurality of windings wound. aroundisaid lower electrode for controlling the temperature of said crystal.

5 A piezo-electric crystal holder comprising a base having connection pins," 5 sealedleivacuated vessel above said base, an upper electrode having a concaved recess, a lower circular electrode sup ported by a central stud,,a .piezo-electric crystal resting on saidelectro'de, an insulating ring'enclosing said crystal and spacing it from said upper electrode,- and a spring co-operating with the concavedirecess on said upper electrode and two vertical retaining membersflfor'securing' the en; tire electrode assemblage to said base, and a heating resistance surrounding said lower electrode r, pe r. electrode, and a spring co-operating with the concaved recess on said upper electrode and two vertical retaining members for securing the entire electrode assemblage to said base, and a heating winding and a measuring winding surrounding-said lower electrode for controlling the temperature lof said crystal.

7. A piezo-electric crystal holder comprising a base having connection pins and a sealed evacuated glass vessel above said base, an electrode supported above said base, a glass ring secured to the upper portion of said electrode, a piezoelectric crystal resting on said electrode, a sec-,- ond electrode spaced by said glass ring and dis-e posed above the said crystaL'and a heatingre si'stance surrounding 'said'first mentioned elec- 'trode, for controllingthe temperature of said crystal. i