Thermostatically controlled crystal oscillator

A thermostatically controlled quartz crystal oscillator comprising an outer housing (1) and a circuit board (2), which board comprises:

• a central part (3) carrying all thermostatically controlled elements of the oscillator, including a crystal resonator in a separate casing (9) and a thermostatic regulator with heating elements (10) and a thermosensitive bridge circuit with a reference arm and a main thermosensitive arm comprising a main temperature detector (11), and
• a peripheral part, separated from the central part (3) of the circuit board (2) by means of through cuts (4), both parts being connected at the ends of the cuts (4) by narrow bridging strips (5),
• characterised in that
• said thermosensitive bridge circuit comprises an additional thermosensitive arm comprising an additional temperature detector (15), wherein said additional arm is coupled to the main thermosensitive arm by a coupling resistor, and in that
• the aforesaid additional temperature detector (15) can be installed at any point of the oscillator, on condition that the temperature at this point (taken under normal outside conditions) is lower than the temperature of the crystal resonator at least by 0.520 C.

A thermostatically controlled quartz crystal oscillator comprising an outer housing (1) and a circuit board (2), which board comprises:

• a central part (3) carrying all thermostatically controlled elements of the oscillator, including a crystal resonator in a separate casing (9) and a thermostatic regulator with heating elements (10) and a thermosensitive bridge circuit with a reference arm and a main thermosensitive arm comprising a main temperature detector (11), and
• a peripheral part, separated from the central part (3) of the circuit board (2) by means of through cuts (4), both parts being connected at the ends of the cuts (4) by narrow bridging strips (5),
• characterised in that
• the crystal resonator in the separate casing (9) is mounted on the bottom of an inner case (6), wherein said inner case:
• is made of material that is an excellent heat conductor,
• is shaped as an inverted open box firmly fixed by its bottom to the circuit board (2), and
• is supplied with heat conductive rods (8), said rods passing through the central part (3) of the circuit board (2) in close proximity to the narrow bridging strips (5),
• the heating elements (10) and temperature detector (11, R5) are mounted on the outer side walls of the inner case (6),
• the rest of the thermostatically controlled elements (16) are mounted on the opposite side of the circuit board (2);
• the open side of the box (6) is covered with a thin cover (12) made of material of a high thermal conductivity, and a heat-insulating space is provided between the cover (12) and the crystal oscillator casing (9),
• a cover (13) is attached to the ends of the heat-conducting rods (8) extending from the opposite side of the circuit board (2),
• a heat-insulating space is provided between the cover (13) and the thermostatically controlled elements located on the surface of the circuit board (2), and
• the cover (13) is made of material of a high thermal conductivity
• the thermosensitive bridge circuit comprises an additional thermosensitive arm comprising
• an additional temperature detector (15), wherein said additional arm is coupled to the main thermosensitive arm by a coupling resistor, and
• in that the said additional temperature detector (15) can be installed at any point of the oscillator, on condition that the temperature at this point (taken under normal outside conditions) is lower than the temperature of the crystal resonator at least by 0.5° C.
• the thermosensitive bridge circuit comprises an additional thermosensitive arm comprising an additional temperature detector (15), wherein said additional arm is coupled to the main thermosensitive arm by a coupling resistor, wherein said additional temperature detector (15) can be installed at any point of the oscillator, on condition that the temperature at this point (taken under normal outside conditions) is lower than the temperature of the crystal resonator at least by 0.5° C.