Abstract: A rotation rate sensor which employs a built-in (i.e. internal) test circuit. The rotation rate sensor includes a piezoelectric structure. Deposited on the piezoelectric structure are at least two pickup high and two pickup low electrodes. A pickup circuit is coupled to the pickup high and pickup low electrodes. During a normal mode of operation, the piezoelectric structure is subject to a rotation about one of its axis. In response, the pickup circuit generates a rate signal which corresponds to the rotation rate of the piezoelectric structure. The test circuit is coupled to the pickup low electrodes. During a test mode of operation, the piezoelectric structure is also subject to a rotation about the axis. But, the test circuit generates at the same time a test signal which is provided to the pickup low electrodes and which corresponds to a pseudo rate of rotation.

Abstract: Servoed accelerometer with isolated voltage torquing having first and second grounds, a servoed accelerometer having a torque coil, and an amplifier for driving said torque coil. The amplifier has inverting and non-inverting junctions. The second ground is coupled to the non-inverting junction of the amplifier. A torque signal supply is coupled to the first ground. A transformer is provided for coupling the torque signal supply to the non-inverting junction of the amplifier and serves to isolate the torque signal supply from the non-inverting input of the amplifier so that the amplifier and polarity of the torque signal are preserved.

Abstract: A passive mass-spring type of sensing device or other such device for monitoring a particular parameter, for example mechanical vibration, is disclosed herein. This device utilizes an electrically conductive coil having a given impedance disposed within a magnetic field in a way which results in relative movement between the coil and the field corresponding to the particular parameter being monitored, whereby to produce a monitoring signal in the form of a voltage which also corresponds to the parameter being monitored. The device includes a circuit arrangement for electronically damping the relative movement recited above in a substantial way while, at the same time, maintaining the monitoring signal at a measurable value.

Abstract: The technique for replacing certain components in a linear accelerometer with an arrangement compatible with all of the other components making up the accelerometer is disclosed herein. The components that are replaced include a potentiometer and mechanical acceleration sensing means which cooperate with one another and which operate on a DC excitation voltage for producing an initial voltage dependent on both the acceleration sensed and the excitation voltage. The arrangement replacing these latter components include acceleration sensing means operating on the same DC excitation voltage for producing an initial voltage which is dependent on the acceleration but which is independent of the excitation voltage and means for adding a percentage of the excitation voltage to this latter voltage for providing a voltage which is dependent on both the acceleration sensed and the excitation voltage, thereby making the arrangement compatible with those components in the accelerometer which have not been replaced.

Abstract: A thin plate-like rotor is mounted on a hub which in turn is attached to the shaft of a motor which drives the rotor at a predetermined rotational speed about a spin axes. A framework is provided for mounting the motor. The rotor has a damping face and an opposite signal face. A damping plate is mounted on the hub in close spaced relation with the damping face. A spring member is disposed between the hub and the rotor so that the rotor is free to move in restrained rotational fashion about one diameter of the rotor. Surrounding air is pumped through the space between the damping face and the damping plate to provide damping of the motion of the rotor about the one diameter. Pickoffs are mounted in the framework in close spaced relation to the signal face of the rotor. The pickoffs provide output indicative of the spacing between the signal face and the pickoffs which corresponds to angular velocity inputs about the separate axes disposed orthogonally with the spin axes.

Abstract: A two axis rate gyro for sensing angular velocity about two input axes includes a rotating disc which is bearing mounted in a framework. A motor is provided for driving the disc rotationally in the bearing mounts. Pickoffs are mounted in the framework which are spaced from the faces of the rotor and oriented along axes which are orthogonal to the two angular velocity input axes. Circuitry is provided for receiving the outputs from each of the orthogonally oriented pickoffs, including circuit means for removing noise in the outputs due to variation caused therein by spacing variation between the rotor faces and the pickoffs resulting from departure of the rotor faces from a flat condition.

Abstract: A structural body is monitored in angular position about at least one axis by utilizing a tilt sensor responsive to tilt about the one axis and a sensor responsive to angular acceleration of the body about the one axis. The tilt sensor also responds to the tangential component of angular acceleration and the angular acceleration sensor output contains a component which results from linear acceleration sensitivity along a cross axis of the angular acceleration sensor. The cross axis of the angular accelerameter is aligned with the sensitive axis of the tilt sensor and a portion of the tilt sensor output related to the ratio of the two sensor scale factors is injected into the angular acceleration sensor output to cancel the cross axis sensitivity. A portion of the angular acceleration sensor output related to the distance between the one axis and the mounting position of the tilt sensor is injected into the tilt sensor output to cancel the tangential component of angular acceleration.

Abstract: Counting apparatus having a transducer for measuring a certain parameter and providing an output, with filtering means for filtering the output from the transducer and decision circuit means connected to the output of the filtering means capable of registering various levels of output from the filtering means and having counting means for counting the various levels of output which have occurred.

Abstract: A structural body is monitored in angular position about at least one axis by utilizing a level sensor and a sensor responsive to angular motion of the body about the axis being monitored. An output indicative of long term angular variations of the body about the axis is provided by the level sensor and short term angular variations are indicated by the output from the sensor responsive to angular motion about the axis. The signals indicative of long term and short term angular variations are combined to provide a broad band output signal indicative of angular position which is immune to high frequency translational variations appearing at the level sensor output, but which is responsive to high frequency angular inputs. The fast response angular sensor output is compared with the slow response level sensor output and an error signal is produced which drives the angular sensor output signal into coincidence with the level sensor output signal.

Abstract: An angular displacement transducer having a mounting base for mounting an inertial element sensitive to low frequency angular displacements and an inertial element sensitive to high frequency angular displacements. The low frequency sensitive inertial mass is a solid rotor device having a pickoff for sensing angular displacement between the solid inertial mass and the mounting base. A feedback centering circuit responsive to the pickoff output maintains the solid inertial mass in a substantially neutral position relative to the mounting base for displacement frequencies below the band of interest and allows the solid mass to move in an open loop fashion within its band of interest. The inertial mass sensitive to high frequency angular displacements is a fluid mass having a pickoff for sensing displacement of the mounting base relative to the fluid mass.

Abstract: A velocity sensor which may be modified to perform a sensing function for either angular velocity or linear velocity. The sensor has a base member which is split into upper and lower halves which are shaped to form internal walls defining an internal channel when joined together. A fluid is disposed in the internal channel and a paddle member is placed in communication with the fluid. Sensing means are present to detect the position of the paddle member as it is urged into motion by the inertia of the fluid mass in the angular embodiment and by the inertia of the paddle member in the linear. An electrical output is provided which is related to the urge to move imparted to the paddle member. The output is used to electrically restrain the motion of the paddle member. The output related to paddle member motion is also integrated to provide a signal related to velocity. Saturation of the integrated output unrelated to velocity is prevented by additional electrical means.