Marconi FM AM Signal Generator
TF995A/5 TF 995A/5 Close to
TF995B TF995B/2 TF995B/5 TF 995B TF 995B/2 TF 995B/5


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Marconi F.M./A.M. Signal Generator TF 995A/5

Frequency range of 1.5 to 220 Mc/s in five bands.

Its output can be un-modulated, frequency modulated, or amplitude modulated; if required, both frequency and amplitude modulation can be applied simultaneously.
The modulation is obtained from either an internal 3-frequency oscillator, or an external source.

The open-circuit output voltage is variable by means of resistive step attenuators from 1 uV to 100 mV at 52 ohms and 1 uV to 200 mV at 75 ohms.
A plug-in 20-db Attenuator Pad, available as an optional accessory extends the range down to 0.1 uV at both impedances.

The high-discrimination tuning required for testing narrow-band systems is facilitated by the inclusion of a fine tuning control.
In addition, small known changes in carrier frequency can be made by means of two directly calibrated incremental frequency controls.
One of these controls gives a stepped adjustment while the other allows continuous interpolation between steps.
On the two highest bands, the stepped control provides shifts of 20 and 40 kc/s in either direction and the calibration marks on the continuous control are only 1 kc/s apart.
On the lower bands, the total shift is determined by a simple division of the reading on both dials.

A high degree of frequency stability has been achieved by use of temperature compensating components; after warm up, drift is less than 400 c/s per minute at a carrier frequency of 200 Mc/s.

The inclusion of a CARRIER on/off switch makes it possible for the Generator output to be temporarily interrupted without affecting the output impedance; this facilitates a number of two signal receiver tests such as intermodulation and blocking which involves the simultaneous use of two signal generators.

Spurious f.m. due to hum is less than 25 c/s deviation, and the low, level of noise modulation makes the TF 995A/5 fully suitable for applications such as adjacent channel testing on receiver systems using a channel separation of 25 kc/s or less.

TF995A-5.jpg (36482 bytes)

Full Manual with Circuits
available Details Below
On Paper CD or Download

Click Here


The Information Consists of  the Following

The Manual contains all circuits for the : -

Marconi FM AM Signal Generator TF995A/5

Close also to the : -
TF995B TF995B/2 TF 995A/5 TF 995B & TF 995B/2.
All 1960 vintage.


GENERAL
 
OPERATION

INSTALLATION

SWITCHING ON AND WARMING UP 

TUNING 

General tuning 
Crystal Calibrator and its use 
Incremental Frequency Controls 
Interpolating Dial 

SETTING UP FOR C.W. OR MODULATED OUTPUT
Continuous Wave 
Amplitude Modulation 
Frequency Modulation 
Simultaneous A.M. and F.M. 

R. F. OUTPUT ARRANGEMENTS
Outputs from 1 uV to 100 mV at 52 and 75 ohms 
Outputs from 2 uV to 200 mV at 75 ohms only 
Outputs from 0.1 uV to 10 mV at 52 and 75 ohms 
Output in terms of voltage developed across external load 

SYNCHRONIZING SIGNAL 

TECHNICAL DESCRIPTION 

R.F. CIRCUITS 

MODULATION SYSTEMS 

MONITORING ARRANGEMENTS 

POWER UNIT 

MAINTENANCE 

ACCESS TO COMPONENTS
 

Removal from Case 
Removal of R.F. Unit Cover 
Removal of Monitor Diode (X2) Cover 

MAINS INPUT CONNECTIONS 

WORKING VOLTAGES
 
Power Supply Voltages 
Valve Electrode Voltages 

DRAWINGS 

CIRCUIT DIAGRAM 

BLOCK SCHEMATIC DIAGRAM 

APPENDIX 

DECIBEL CONVERSION TABLE

* Note Marconi did not include layouts in this manual *

Full Manual with Circuits
available Details Below
On Paper CD or Download

Click Here


If your model is the TF995A/5  it will have a valve line up as below : -

Six; Type 6AK5, Pentodes.
One: Type 6AK6, Pentode.
One: Type 6AL5, Double Diode.
One: Type 6AU6, Pentode.
One: Type EF86, Pentode.
Two: Type 12AT7, Double Triodes.
One: Type 5Z4G Full Wave Rectifier.
One: Type OA2, Voltage Stabilizer.
One: Type 5651, Voltage Stabilizer.

If your model is the TF995A it will have a valve line up as below : -

If it is the TF995A/1 it has an extra valve a 12AT7 double triode.

Six: Type EF95 Pentodes.
Two: Type 6AK6 Pentodes.
One: Type 6AU6 Pentode
One: Type QS15O/15 Voltage Stabilizer.
One: Type 5Z4G Full Wave Rectifier,
One: Type D77 Double Diode.

Marconi FM AM Signal Generator TF995A/5 TF 995A/5 
Close also to the TF995B TF995B/2 TF995B/5
TF 995B & TF 995B/2 TF 995B/5.
All 1960 vintage.
Manuals are Available Worldwide as a Download on CD or Paper Copy.

For the TF995A an earlier 1954 model or the TF995A/1 1955 Click Here

The Manual Contains 48 pages including the circuit.

Manual 48 A4 pages worldwide

Printed Paper Copy or on CD are Plus Postage.

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We do all we can to provide the very best that is available for you.
But in the unlikely event that any data should not be as you expected.
A refund is always available. Kind Regards Allen and Alanna.


Manuals are Available Worldwide as Paper Copy on CD or as a Download

Thank you for your interest. Allen and Alanna G0RIT
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Revised: January 20, 2016