This invention is directed to a Doppler radar technique for monitoring the revolutions per minute of rotating objects. More particularly, this invention is directed to a contactless system for the monitoring of the revolutions per minute of the shaft of a gas turbine using a Doppler radar technique. BACKGROUND OF THE INVENTION Presently used methods of monitoring the revolutions per minute of rotating objects such as gas turbines rely upon the use of devices or systems which are physically coupled to the turbine through moving parts. Because physical wear is involved, the devices and systems wear out in time, require maintenance to correct errors, and frequently need replacement. Some systems are coupled to the rotating object through moving parts, other systems involve the use of rotary transformers, and still other systems utilize magnetic pickups. Although all of these techniques are effective in their own right~ and for the purposes required, they all have shortcomings. The use of rotary transformers is frequently satisfactory, but the cost of additional equipment makes these techniques expensive. Magnetic pickup systems are also useful but suffer from installation problems and high cost. Stroboscopes are often used to synchronize a flashing light with the shaft rotation, making the shaft appear stationary. While this instrument offers a non- contacting method of rotational velocity measurement, thereby eliminatin~ wear of moving parts, it has the disadvantage of being able to synchronize on harmonics of the fundamental shaft speed, thus requiring the user ~i~ --2-- ~7 . . - - . .. , to know the approxim2te velocity at which the object, e.g. shaft, is rotating in order to avoid error. While the stroboscope lends itself to discrete monitoring, it is impractical for continuous monitoring or speed control. SUMMARY OF THE INVENTION The inventors have developed a non-contact method for measuring and monitoring the speed of rotation of a rotating object such as the shaft of a gas turbine which has reliability and accuracy, requires an insignificant alteration to existing installations and is economical to install. The contactless method of monitoring the rotation of the rotating object such as a gas turbine shaft is done utili~ing a Doppler radar technique which involves no moving parts and has solid-state reliability. The principle of operation is based on the shift in frequency resulting from the reflection of a radio signal from a moving body. The frequency difference provides a direct correlateable indication of the speed of the moving body, for example, a rotating turbine shaft. When a rotating object such as a turbine shaft is beamed at an angle to the axis by a Doppler type radar, the presence of any mechanical imbalance in the shape of the rotating object (e.g. shaft) for example balancing holes, screws, keyways, slots or protrusions, surface roughness, etc. gives rise to bursts of Doppler signals which can be readily identified and evaluated by signal processing. Any beam angle will work and the strength of the returned signal is roughly proportional to the cosine of the angle. According to experimented evidence, a beam angle of 90 may not necessarily be optimum - the optimum angle is dependent on shaft discontinuity geometry. Each revolution of the object produces an identical pattern and these may be monitored using a counter to read the revolutions per minute of the object (e.g. turbine shaft). The degree of electrical imbalance required to give a useful signal is very small and one can usually rely on normal surface roughness of the object to give adequate reflection for satisfactory operation of the technique, unless discontinuities exist which give larger bursts of a return signal. The invention is directed to a method of measuring, controlling and monitoring the rotational speed of a rotating member comprising employing a Doppler effect transceiver to measure the rotation speed of the rotating member, feeding the signal from the Doppler transceiver into an amplifier, subsequently into a wave shaper, subse~uently into a digital multiplier, subsequently into a readout and comparator, and finally into control circuitry which, if the rotational speed of the object ; ~20 exceeds a predetermined speed, shuts down the member. The invention also includes a method of measuring, monitoring and controlling the rotational shaft speed of a turbine by utilizing a Doppler transceiver which detects discontinuities on the surface of the rotating shaft of the turbine, whereby the audio output of the Doppler transceiver is amplified and is then fed into a wave shaper which eliminates the harmonics, renders the signal compatikle with logic being used in the system, the signal being multiplied by a digital frequency multiplier and being fed into a readout, the - 4 - - . - - ~ $ ~ ~ L ~ fre~uency of the signal being fed into the readout whereby it is monitored by a comparator, and if the frequency exceeds a predetermined set point, the comparator produces a pulse which is utilized to activate speed control circuitry attached to the rotating shaft of the turbine. A 3 milli watt transceiver can be used. The output of the transceiver can be directed onto the rotating shaft by a horn, or an antenna system, and can be shielded to prevent the movement of objects other than the rotating shaft being monitored from affecting the transceivers electromagnetic field. The invention is also directed to a method of determining the rate of rotation of a rotating object comprising utilizing an electronic measuring means based on the Doppler effect for transmitting a signal for reflection off a rotating object and receiving the signal reflected from the rotating object and mixing the signal to produce an audio signal with a frequency proport- ional to the rotational speed of the rotating body. In the invention described above, the output signal from the Doppler measuring unit can be amplified to 5 Volt (5 V) peak whereby it is easily shaped for TTL compatibility using a one shot and is reduced to a fundamental harmonic by a fre~uency divider circuit. The method can employ amplifier/wav~ shaper means to produce one pulse per revolution and such pulses are counted for one second utilizing an X 60 multiplier means. Multiplication can be accomplished by dividing the period of the incoming frequency by the multiplicand, a 10 MHz pulse train being gated by the incoming frequency into a counting circuit, the aacumulated pulse count, for one period being then divided by the multiplicand and being fed into a down counting circuit clocked at 10 MHz, the resulting output frequency therefore being greater according to the multiplicand ratio than the incoming frequency. A digital readout means can be used whereby the multiplier is divided into three decades to reduce resolution error. The readout value can be compared with a thumb wheel switch means value preset by means of digital circuitry, and if the readout value exceeds the set on the thumb wheel switch, a latch relay means can be pulsed which in turn closes a set of contacts to shut down the rotating object. The invention is also an electromagnetic system operable for measuring, and monitoring the rotational speed of a rotating object comprising in combination the following elements: (1) A continuous wave Doppler transceiver which is operable to transmit an electromagnetic signal towards the rotating object. The Doppler transceiver is operable to receive an electromagnetic signal reflected from the rotating object and produces an audio fre~uency output electrical signal. The period of the audio frequency output electrical signal is inversely proportional to the rotational speed of the rotating object. (2) Amplifier ~ and wave shaper means which receive the audio frequency output electrical signal from the Doppler transceiver for generating a train of electrical pulses. - 6 - . . - . ., ~LA ~ (3) Multiplication means for increasing the pulse repetition rate of the pulse train. (4) Pulse counting means for counting the total number of pulses output from the multiplication means in a desired time period (5) Comparison means for comparing the total number of pulses counted in a given period of time with a pre-selected value. The electromagnetic system described above may further 10 include control means connected to the output of the comparison means. The control means are operable for controlling the rotational speed of the rotating object. The rotational speed of the object is increased if the number of pulses counted by the pulse counting means in the desired time period is less than the pre-selected value. However, if the number of pulses counted by the pulse counting means in the desired time period is greater than the pre-selected value then the control means reduce the rotational speed of the object. According to another aspect of the invention, there ; is provided hn electromagnetic apparatus operable for measuring and controlling the rotational speed of a rotating ; object, comprising in combination the following: (a) A continuous wave Doppler transceiver comprising a radar frequency electromagnetic transmitter and a radar fre~uency electromagnetic Feceiver. The transmitter is operable to transmit a radar frequency electromagnetic signal towards the rota~ing object via an antenna system. The receiver is operable to to receive at least a portion of the signal reflected ~i - 6a - from the rotating object. The reflected signal is mixed with a portion o~ the transmitted signal in the receiver so as to generate an output audio frequency electrical signal whose period is inversely proportional to the rotational speed of the rotating object. (b) A low noise electronic amplifier coupled to the output of the transceiver for amplifying the magnitude of the output audio signal of the transceiver. (c) Wave shaper means connected to the output of the amplifier for generating a train of electrical pulses. An integer number of pulses corresponds to each revolution of the rotating object. (d) Frequency multiplier means are connected to the output of the wave shaper means for multiplying the pulse repetition rate of the pulse train which appears at the output of the wave shaper means. The pulse repetition rate of the pulse train is multiplied by a second integer and thereby reduces the time required to make a measurement of the rotational speed of the -~ rotating object. The output pulse train from the ~ frequency multiplier means has a pulse repetition rate ; exceeding the pulse repetition rate of the input pulse train by a fa~tor equal to the second integer. (e) Digital readout means, connected to the output of the frequency multiplier means for counting the number of pulses at the output of the frequency multiplier means in a desired period of time and thereby providing an indication of the number of revolutions of the rotating object in the desired period of time. _ ~ - 6b - ~ . ,. ' ~ , . ., . ., - . : :': . (f) Comparison mear.s coupled to the readout means operable for comparing the number of revolutions of the rotating object in the desired period of time with a predetermined number. (g) Control means connected to the comparison means for controlling the rotational speed of the rotating object. In the system described above, the frequency multiplier means may comprise: (a) First means for generating a first pulse train of known pulse repetition rate and period. (b) Second means, coupled to the first pulse train generating means, for generating a second pulse train having a pulse repetition rate equal to the known pulse repetition rate of the first pulse train multiplied by the reciprocal of the second integer. (c) Means for gating the second pulse train by the input pulse train to the frequency multiplier means. (d) Counting means, coupled to the output of the gating means, for counting the number of pulses output from the gating means during a selected period of time corresponding to the period of the input pulse train. (e) A down counting aircuit, coupled to the output of the counting means, the down counting circuit being clocked at the ~irst pulse train repetition rate, the output pulse train o~ the down counting circuit, being the output pulse train of the frequency multiplier means, having a pulse rate exceeding that of the input pulse train by a multiplicand equal to the second integer. . -, :.,.. . ~ ', .- - ' . : _ WINGS In the drawings: FIGURE 1 represents a block diagram of a digital readout tachometer. DETAILED DESCRIPTION OF THE INVENTION_ A transceiver, while mainly used in the past for the measurement of linear velocities, is utilized for the measurement of rotational velocities. The module transmits a microwave signal, and mi~es the signal reflected from a linearly moving or rotationally moving object to produce an audio signal whose period is inversely proportional to either the linear or the rotational speed of the object being observed. This signal is then processed by analog and digital circuitry to give the desired readout. For angular velocity measurement, the transceiver is used to detect discontinuities on the surface of the rotating member, e.g., shaft surface. Even minute discon- tinuities on a rotating member have been shown to produce audio signals. Using a 3 mW transceiver, signals of the order of tens of mV- peak have been measured from a machined shaft and in the order of tens ofJuV-peak from a rotating he~a~onal nut. The main advantage of using a Doppler transceiver system is that it is non-contacting. The rotating member e.g. turbine shaft, does not have to drive any mechanisms, and no modifications have to be made to the member, that is, the attachment of magnets or reflective tape. The output of the transceiver merely has to be directed onto the member via a horn, or other antenna system, and shielded to prevent the movement of objects other than the member : ' -- 7 -- .. .. , : ' ` ~ ~ ' ' being monitored from affecting the transceivers electromagnetic field and introducing extraneous signals. The economics of using a Doppler transceiver also make it attractive over other RPM measuring devices available on the market. Since the receiver detects discontinuities on the rotating surface, the only real disadvantage of this system is that the readout may be a multiple of the actual velocity of the rotating member. This problem is easily overcome by using analog circuitry to eliminate the lower level discontinuity si~nals and then using digital circuitry to eliminate whatever harmonics are left. However, the unit must be individually calibrated for each shaft to be monitored. As shown in Figure 1 (which shows a block diagram of the digital readout tachometer) the audio output of the Doppler transceiver is amplified and is then fed into the wave shaper which eliminates the harmonics as described previously, and makes the signal compatible with the logic being used. The signal is then multiplied by a digital frequency multiplier and is fed into a readout. The fre~uency of the signal being fed into the readout is monitored by a comparator. If this frequency exceeds a predetermined set point, the comparator produces a pulse which is used to activate the turbines speed control circuitry. TTL was used to construct the logic, however other types of logics such as CMOS could also have been used. It is also conceivable that a CPU could have been used in place of the logic. The Doppler transceiver that has been used is a preconstructed microwave device that is now commonly - 8 - . ., .... ,. . , , . ~ available on the electronics market-place. The Doppler transceiver transmits a signal in the 10 GHz region, receives the reflected signal and mixes the signals to produce an audio signal whose frequency is proportional to the linear or rotational speed of the moving or rotating body at which its transmitted beam is directed, and is also proportional to the number of discontinuities on the surface of the rotating body. Even minute surface discontinuities produce measurable audio signals. A low noise amplifying circuit is required since the output signal of the Doppler transceiver unit in some cases may be quite small (10uV peak). Once the signal is amplified to SV peak, it is readily shaped for TTL compatibility using a one shot and is reduced to its fundamental harmonic by a frequency divider circuit. Any frequency Doppler module may be used. The system also uses an amplifier/wave shaper which produces one pulse per revolution of the rotating member e.g. turbine shaft. To obtain a readout in revolutions per minute, it would normally be necessary to count pulses for one minute. This is a rather long and impractical counting time and was considered by the inventors to be potentially detrimental. This was so because any circuit used to detect excessive speed of the member e.g. turbine shaft (overspeed detector) would be connected to the counting circuit and there was therefore the possibility of the turbine, for example, running a full minute at an excessive and possibly dangerous speed before the shut down sequence would be initiated. A more reasonable solution would be to count for only one second, thus requiring an x60 multiplier. ~ . : A computerized study showed that it would be best to divide the meter range into three decades, 30 to 300, 300 to 3,000 and 3,000 to 30,000 RPM. The multiplier was assigned a different multiplicand for each decade: 600 for 30 to 300, 60 for 300 to 3,000 and 6 for 3,000 to 30,000. The result of this decadization was to assure a maximum quantitization error of 0.1 percent in the multiplier. This technique also reduced the resolution error in the readout. The multiplication can be accomplished readily by dividing the period of the incoming frequency by the multiplicand. A 10 MHZ pulse train is gated by the incoming frequency into a counting circuit. The accumulated pulse count for one period is then divided by the multiplicand (M) and fed into a down counting circuit clocked at 10 MHZ. The resulting output frequency will then be M times greater than the incoming frequency. The invention also uses a readout which consists of six digits (00000.0). The multiplier, as explained previously, is divided into three decades to reduce resolution error. The reduction in resolution error can be accomplished as follows: whenever a digital readout is used, there is always an uncertainty in the last digit. Using the three decade system, the first decade (30 to 300) has a resolution of +0.1 RPM (0.33% maximum). The second ~ decade (300 to 3,000) has a resolution of +1 RPN (0.33% ; ~ maximUm). The third decade (3,000 to 30,000) has a resolution ; of +~10 RMP (0.33% maximum). The third decade cannot have its resolution reduced to +l RPM without increasing the multiplier quantization error beyond acceptable limits. i 10 . - :: Fin~lly, the system utilizes a comparator and a shut-down actuator. The readout value and thumb wheel switch values can be compared quickly and easily utilizing digital circuitry. If the readout value exceeds that set on the thumb wheel switches, a latching relay is pulsed, closing a set of contacts to initiate the shut-down sequence. The maximum delay between overspeed occurrence and shut- down initiation will be one second. Normally, no significant damage to the rotating member e.g. turbine can occur in one second. The latching relay is manually reset once the shut down has been initiated. To facilitate easy repair and maintenance in the field, the circuits are sub-divided into a number of small boards, each counting from 3 to 5 IC's per board. Edge connectors can be used to enhance maintenance and repair. The system described above has been bench tested at the University of Regina, Regina, Saskatchewan, Canada, and has been found to be very successful. The range of the monitor is easily extended and probably can be adapted into a hand-held tachometer by using memory chips, etc. The system has been found to be reliable and has resulted in a considerable cost saving over the mechanical system previously used at this station. While particular embodiments of the present invention have been shown and described, it is apparent that various changes and modifications may be made, and it is therefore intended in the following claims to cover all such obvious modifications and changes as may fall withln the true spirit and scope oE this invention. ~ .