EMRFD Chapter 9 Errata.

(7Jan08)

Chapter 9 figures:   (This is a comment rather than errata.)  Many of the schematics in this chapter are missing the semiconductor types used.  We will fill in the details later, but the list is small.  The usual NPN is (you guessed it) a 2N3904 while the 2N3906 is the PNP.   The JFET of choice is the J310, although the metal can version, the U310, is the better choice for common gate amplifiers.  See Chapter 6 for comments on such amplifiers.  The op-amps are either the LM837N or the 5532.   The LM837N is preferred for the early stages where noise is critical. A 10 pF chip capacitor between op-amp output and the inverting input will usually cure any tendency toward instability.  (24Feb03, update 2Mar03)

p9.6, Fig 9.7G.  There is a corner of the box missing, just above the "G".  (20Mar03)

p9.25, Fig 9.38.  The oscillator FET is a J310, not a 4310.  (24Feb03)

p9.29, Fig 9.49.  The caption is not correct.  The caption should read "Phase errors of Fig 9.48 network pair."  (20Mar03) 

p9.29, Fig. 9.50.  The caption is not correct.   The caption should read "A pair of all-pass networks that provide at least 21 dB suppression from 360 to 2050 Hz."    (20Mar03) 

p9.34, Fig 9.62.   The caption is not correct.   The caption should read "A basic miniR2 schematic. This simplified version uses some different parts values and requires matching of the diplexer components."   (20Mar03)

p9.34.    Fig 9.62.   The upper diode ring mixer should have the ground and IF terminals exchanged.    This error is exactly the same drafting problem that appeared on page 9.46.    This is shown below.     See "p9.46"  (10 Oct 05)

p9.34.    Fig 9.62.    There are resistor and capacitor values missing for the first op-amp in the signal chain in both channels.   Both channels are, of course, identical.    The feedback resistor is 100K, the input R is 27K, and the capacitor is 0.12 uF.   (These are the values extracted from Fig 9.66.)   The op-amp type used is a 5532 or similar low-noise part.   But feel free to experiment and try other types.    That is, after all, what this book is all about!   (17 Oct 05)      

p9.34,  Fig 9.62.    There are some missing parts values from figure 9.62.  The capacitor from the volume control to the non-inverting input of U2a is non-critical. 0.1 uF works well, as shown in figure 9.74.  The capacitors across the low-pass filter inductors are optional.  They were not included in the particular receiver that was used to draw the schematic, but have been used in other receivers to provide a steeper rolloff above the audio passband.  This is a great little circuit and we have built a dozen receivers with this schematic, each one with slight variations in component values.  We hope that after studying Chapter 9 and doing some experiments at the bench, the
reader will be comfortable comparing schematics and making component selections and substitutions.  It is particularly gratifying to experiment with filter component values while listening to real signals on the headphones.  Here are two low-pass filters that we have used in similar receivers, along with calculated responses.  (19Feb 06)        





 The response assumes inductor Q-u of 10, which is probably way too high for these inductors.    A better value might be 3.    This is not a major problem in a low pass design.  
                       
p9.35,  Fig 9.64.     L1 in the figure mentions 36t on a T30-6.   This should be ignored; it is a remnant from early drafting and early experiments.    The frequency dependent data in the table should be used.    (7Jan08)  

p9.36.    Fig 9.66.   The upper diode ring mixer should have the ground and IF terminals exchanged.    This error is exactly the same drafting problem that appeared on page 9.46.    This is shown below.    See "p9.46"    (10 Oct 05)

p9.38, Fig 9.69.     The two output capacitors at the top of the page, connected between the op-amp outputs and 10k resistors, should be 10 uF electrolytics.  The 0.1uF value shown in the schematic is a typographical error.  Since these capacitors are after the summing network in the phasing receiver, they are non-critical, but should be near 10 uF for the ASP board to have a wide frequency response when driving medium impedance loads near 500 ohms.  They are clearly and correctly shown as electrolytics in both the layout view figure 9.70 and the photograph figure 9.71.  (19Feb07)          

p9.41, Fig 9.74.   Two dots are missing in the schematic.   Add the dots as shown in red.   (16Aug03)
 

    
p9.42, middle col., 2.5 inches up from bottom.  Replace "needed for to optimize"  with "needed to optimize" (16Dec03)

p9.43. Fig 9.78.   The power supply decoupling resistor in the lower right corner of the schematic should be 10 Ohms rather than 10K. (16Aug04)              

p9.46, Fig 9.83.   There was an error in the figure relating to the use of the TUF form mixers.   LO should be applied to the end pin next to the grounded pin.   Hence, the drawing changes, as shown here:

 Fig 9.83 changes.   (17Dec03)    

p9.47, right col, 3.0 inches down from text top:   Replace "1.414 time" with "1.414 times"   (16Dec03)